HP 185B Service manual

I.

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203210-

222-

@

1

1.

2

1

thru 3 01000

MANUAL

250-

317-00901 thru

CHANGES

MODEL 185B

OSCILLOSCOPE

Manual Serial Prefixed: 144-

Manual Printed: OCT 1962

1

thru 6

1

thru 8

432446-

525-

1

thru thru 12

1 1

thru 14

11

230245-

1

thru 4 348-

1

thru 5 430-

1

thru 9

1

thru 10

534-

1

thru 13, 15

28 December 1965

Supplement A for

185B-901

Serial Prefix Make or Number Manual Changes

203210222230-

1

2

1. 1

thru 3

1

thru 4

Manual Changes Model 185B

Serial Prefix Make

or

Number Manual

,250-

317317-00901 thrul 01000

348-

I

Cbsnges

1

thru 6

lthru7

1

thru

8

1

thru9

Page

2/9

432446525534-

1

thru

11

1

thru 12

1

thru 14

1

thru 13, 15

245-

ERRATA Add the following:

(cont'd)

CHANGE

CHANGE 2

1

Reference Desienation

C123

C160

L115 C425

C426

C427

C614

C615

C616

L608

1

thru 5

A302: HV Transformer Assembly: includes C309, C310, T301, V303, and V304;

Stock No. 185A-llA; Mfr. 28480; Mfr. Part No. 185A-llA; TQ C309, C310: Same description and @ Stock No. L603: Same description and T301: HV Transformer;

130B-llB-1; TQ 1;

V303, V304: Tube electron: 5642; @Stock No. 1920-0001; Mfr. 28480; Mfr.

1920-0001; TQ 2; RS 2.

Section VI and schematic diagrams,

Add the following:

Value

0.05 pf

pi

0.005

360 ph

0.05

pf

8200 pf

0.05 pf

pf

0.05

pf

0.1

pf

100 ph

(Note: For instruments

under CHANGE 2 except Q209.) Section VI and schematic diagrams,

C616: Delete. QlOl, Ql02, Q103, Q209: Change to

Mfr. 01295; Mfr. Part No. 2N388A.

R611: Change to

28480; Mfr.

The Internal Graticule Cathode-Ray

Model 185B Oscilloscope. The CRT formerly supplied, without internal graticule,

is

still available

Figure

5-26,

Change wiring

430-

@

RS

1.

C: fxd, and junction of R128 and +lOOV.

C: fxd, and ground.

Coil: fxd, RF, 360 ph. (On+6.3VlinebetweenR107 andC110.

C:

pin 10 [+12. 6V] , and ground.)

C: fxd, cer, 8200 pf, 500VDCW. (Between

C-IOOVJ

C: fxd,

J1,

C: fxd, cer, 0.05

between C: fxd,

between +12.6VF and ground. C: fxd, cer, 0.1

between +12.6V [BRN wire] Coil: fxd, RF, 100 ph.

this change] and C607 on -12.6V line.)

cer,

0.05

cer,

0.005

)

fxd, cer, 0.05

,

and ground

cer,

0.05 pf, +80% -20%, 1OOVDCW. (Between

pin 5 [-12.6V] , and ground.)

-

12.6V and ground.

cer,

0.05 pf, +80% -20%, 1OOVDCW.

serial

prefixed 222- and above, make

@

Stock No. 2100-0351;

Part

No. 2100-0351.

as

Option 05. This change obsoletes Option 03.

as

shown

in

1

thru 10

as

C312; change TQ column to 3.

@

Stock No.

Stock No. 130B-llB-1; Mfr. 28480; Mfr.

pf,

20%, 400VDCW. (Between ground

pf,

+80% -20%, 1OOVDCW. (Between

pf,

+80% -20%, 1OOVDCW. (On A602

pf,

+80% -20%, 50VDCW.

Tube

Figure

1.

as

L601, L602.

Description

)

500VDCW. (Between T103, pin 8,

J1,

pin 9

)

(On

A602

)

(On

S601A

,

and ground.)

(On

A602 between C614 [added by

all

component changes listed

@

Stock No. 1851-0024; Transistor 2N388A;

R:

var,

WW,

is

now supplied

4K ohms,

as

a

IO%,

standard part of the

1;

Part

J1,

RS

0.

No.

Part

@

1150-0052

0150-0014

9140-0038 0150-0096

0150-0082

0150-0096

0150-0121

9 140-0029

4W; Mfr.

($3

No.

Stock No

28 December 1965

Manual Changes Model 185B Page 3/9

Serial Prefix Make or Number Manual Changes

203210222230245-

CHANGE 2

(con t

'

d)

1

1.

2

1.thr1.1 1

1

r

thru 4

hru

I

-

3

5

7

I

1

I

Serial Prefix or Number

250317-

317-00901 thru

O1OOO

348-

430-

L601

35UH

n

R613

IO

-

T

Make

Manual Changes

-

4

+

12.6VF

Serial or Number Manual Changes

432446-

0603

Prefix

525-

534-

(k

Make

1

thru

11

1

thru

12

1

thru 14

1

thru 13.15

CHANGE 3

I

+12.6VF

I

Section

VI

and schematic diagrams,

Q209: Change to

Mfr. Part No. 2N2218.

Q603: Change to

Mfr. PartNo. 2N384.

R436: Change to

Mfr.

Part

R604: R607: Change to

R610: Change to Add the following:

Change to factory selected value.

Mfr. 01121; Mfr.

Mfr.

28480; Mfr. Part No. 0767-0011.

C134: C: fxd, elect, 20

Mfr. Part No. 40D-181-A2. and R155. reference designation corrections.

110

Figure

@

Stock No. 1854-0013; Transistor: silicon, 2N2218; Mfr. 04713;

@

Stock No. 1850-0041; Transistor: germanium, 2N384;

@

Stock No. 0819-0023; R: fxd,

No. 0819-0023.

$3

Stock No. 0683-3015; R: fxd, comp, 300 ohms, 5% 1/4W;

Part

@

Stock No. 0767-0011; R: fxd, metal film, 20K ohms, 5%, 3W;

)

Note: See Errata section of this manual change sheet concerning

i.

WW,

5 ohms, 5%, 55W; Mfr. 28480;

No. CB 3015.

pf,

25VDCW; @ Stock No. 0180-0076; Mfr. 56289;

(Connects between ground and junction of R154

Mfr.

02735;

28 December 1965

Manual Changes Model 185B

Page

4/9

Prefix

Serial or Number Manual Changes

203210222230245-

CHANGE

(cont'd)

3

Make Serial

1

1.

2

1

thru 3

1

thru 4

1

thru 5

C617: C: fxd,

Mfr. Part No. SM-62-N1500. and R610.

5604: Connector: BNC; @ Stock No. 1250-0083;

UG-l094/U.

L116: Coil: fxd, RF, 1OO'ph;

3100-15-101.

R268: R: fxd, comp, 82K ohms,

Mfr. Part No. EB 8231.

or Number Manltal-€hm@s

Prefix

2 50317-

317-00901 thrul 01000

I

1

thru 6

1

thru

1

thru

1

thru 9

Make

7

8

432446-

525-

534-

1

E-kL-i

cer,

62

pf,

lo%,

SOOVDCW; @ Stock No. 0150-0087; Mfr. 91418;

(Connects between ground and junction of R607

)

Mfr.

(Insert in line between J601 and A602 [circuit board 185E65Pl

(Insert in line between SlOlA and junction of R154 and R155.)

@

Stock No. 9140-0029; Mfr. 99848; Mfr.

lo%,

1/2W; @ Stock No. 0687-8231; Mfr. 01121;

(Connect

a8

shown in Figure 2.)

91737; Mfr. Part No.

thru

11

thru 12

thn

14

th.ru

13,15

Part

No.

.

)

CHANGE 4

28 December 1965

Section

Figure

L

Figure 2.

VI

Add C244: C: fxd, CR107, CR108, CR112, CR113, CR114: Change to Add CR223: Diode: germanium;

QlKChange to @ Stock No. 1854-0003; Transistor: silicon; Mfr. 28480; Q201: Change to Q603: Change to

Disconnect R272 end which attaches to junction

and schematic diagrams,

cer,

0.1

pf,

40%

Mfr. 56289; Mfr. Part No. 33C41. silicon; Mfr. 28480; Mfr. Part No. 1901-0040.

1910-0016. (Connects between R267 and S203A; anode side connects to S203A.

Note:

Do

not add CR223

Mfr. Part No. 1854-0003.

@

Mfr. Part No. 1850-0062. Mfr.

Part

5-17,

to junction of R501 and S204.

Stock

@

Stock

No. 1850-0029.

if

instrument

No.

1850-0062; Transistor: germanium; Mfr. 28480;

No.

1850-0029; Transistor: germanium; Mfr. 28480;

-20% 50VDCW; @ Stock (Connects in

@

Stock

No.

1910-0016; Mfr. 28480; Mfr.

serial

prefix

of

Q210 and R255B and reconnect

parallel

($3

Stock No. 1901-0040; Diode:

is

No.

0150-0084;

with

CR221.

250- or above.

)

Part

No.

)

Manual Changes Model 185B

Page 5/9

I

Serial Prefix Make

or

Number Manual Changes

250-

317-00901 thru

348430-

CHANGE 5 Figure 5-29 and Section

A

Q401, Q402,

9405,

Q416: Change to

PNP, selecte3 YTfr. 28480;

VI,

Yfr.

1

thru 6

1

thru 9

1

thru

10

’@

Stock No. 5080-0427; Transistor: germanium,

?art

FTo.

5080-0427.

432-

1

thru

11

thru 14

CHANGE 6 Figure 5-29 and Section VI,

to

‘$3

CR407, CR410, CR413: Change

Mfr.

10%;

R444: Change to

28480; Mfr. Part No. 1902-0034.

@

Stock No. 0758-0015;

Stock No. 1902-0034; Diode: breakdown, 5.76V,

R:

fxd, metal film, 220 ohms, 5%

1/2W;

Mfr. 28480; Mfr. Part No. 0758-0015.

R458: Change to

‘$3

Stock No. 0758-0014; R: fxd, metal film, 180 ohms, 5%, 1/2W;

Mfr. 28480; Mfr. Part No. 0758-0014.

R463: Change to

$3

Stock No. 0816-0022; R: fxd,

ww,

1500 ohms, 576 1OW;

Mfr. 28480; Mfr. Part No. 0816-0022.

Section

VI

and schematic diagrams,

Add the following:

L114: Core: ferrite bead;

56-590-65/4A.

(Connects in

of C151 and R179.

R196: R: fxd, comp, 10 ohms, 1096, 1/4W;

Mfr. Part No. CB 1001. (Connects in and ground.

)

R447, R459: R: fxd, metal film, 680 ohms, 57% 1/2W;

Mfr. 28480; Mfr. Part No. 0758-0031.

‘$3

Stock No. 9170-0029; Mfr. 02114; Mfr.

series

)

with C152 between capacitor and junction

@

Stock No. 0684-1001; Mfr. 01121;

series

with C141 between capacitor

($3

Stock No. 0758-0031;

Part

No.

(Connect R447 between -12.6V output and junction of Q415 and CR410; connect R459 between ground and junction of Q412 and CR407.

)

Table 6-2,

Delete @ Stock No. 185A-12G. Add the following:

Probe: Clip Adapter; Probe: Clip;

@

9

Stock No. 5040-0403; Mfr. 28480; Mfr.

Stock No. 5040-0404; Mfr. 28480; Mfr.

Part

No. 5040-0404.

Part

No. 5040-0403.

CHANGE

7

Figure 5-17 and Section VI,

28 December 1965

pf,

40%

Add C237: C: fxd, cer, 0.1

Mfr. 56289; Mfr. Part No. 33C41. +12.6VF and CR209.

CR201: Change to @ Stock

)

No.

-20%, 50VDCW; @ Stock No. 0150-0084; (Connects between ground and junction

1901-0050; Diode: silicon; Mfr. 28480; Mfr.

of

Part

No.

1901-0050.

CR210, CR212, CR216: Change to

($3

Stock No. 1901-0040; Diode: silicon; Mfr. 28480;

Mfr. Part No. 1901-0040.

CR219: Change to

@I

Stock No. 1901-0025; Diode: silicon; Mfr. 28480; Mfr. Part

NO.

1901-0025.

CR220: Change to @ Stock No. 1902-0068; Diode: breakdown, 80.6V, 5%; Mfr. 28480;

Mfr.

Part

CR221: Change to

Mfr.

Q207: Change

Mfr. 348-

No. 1902-0068.

@

Part

No. 1902-0074.

to

($3

Part

or

above.

Stock No. 1850-0091; Transistor: germanium, 2N2048; Mfr. 56289;

No. 2N2048. Note:

Stock No. 1902-0074; Diode: breakdown, 7.15V, 5%; Mfr. 28480;

Do

not change Q207

if

instrument

serial

Prefix

is

203210222-

1

2

1,

1.thru

Manual Changes Model 185B

250- lthru6 317-

317-00901

3

01000

1

thru

1

thru thru

7

8

Page

6/9

432-

1

thru

1

thru 12

1

thru 14

11

23024 5-

CHANGE 8

CHANGE 9

CHANGE 10

1

thru 4

lthru5

Figure 5-29 and

Q418, Q419:

Mfr.

Section VI, Change to

Part

No. 1850-0040.

$9

Stock No. 1850-0040; Transistor: 2N383; Mfr. 28480;

Tables 6-1 and 6-2,

C402: Change to

CR136: Change

$9

Stock No. 0180-0164.

to

@

Stock No. 1901-0050.

Figure 5-17,

A

Q207: Change type to 2N2635.

Figure 5-26 (as modified by CHANGE 2),

pf);

Add: electrolytic capacitor C618 (3000

R613/L607 junction and ground (observe polarity). C618

connects between +12.6VF

is

clamps to left-side gusset below CALIBRATOR switch. Wire from board A602

is

BRN/ORN.

mounted

at

right of

by

+

lead to

cable

Tables 6-1 and 6-2,

Add C618:

Mfr. 56289; Mfr.

Q207: Change to @ Stock No. 1850-0158; Transistor: GE, PNP, 2N2635; Mfr 04713.

A

(Replacement for discontinued item.

($3

Stock No. 0180-0271; C: fxd, elect, 3000

Part

No. 34D308H015JT4.

)

(EIA

type 2N2048 may

pf,

-10% +loo% 15VDCW;

if

used

available.

Figure 5-13,

C160 (added in CHANGE 1): Change value to 2.2

pf.

Add: C161 (200 pf); capacitor connects between ground and junction of R147/CR137.

Figure 5-26,

to

2.2

C615 (added in CHANGE 1): Change value

fl.

Tables 6-1 and 6-2,

C160, C615: Change to

Mfr. 56289;

Mfr.

Add C161: C: fxd,

($3

Stock No. 0160-0128; C: fxd,

Part No. 5C15.

cer,

200 pf, 5%, 500VDCW; Mfr. 56289; Mfr.

cer,

2.2

1.4

20%, 25VDCW;

Part

No. 40C.

)

CHANGE

11

CHANGE 12

28 December 1965

Figure 5-13,

C130: Change value to 56 pf. C159: Change value to 3300 Q102: Change transistor type

pf.

to

special 2N1310,

R142: Change value to 47K.

Tables

6-1 and 6-2,

C130: Change to

Mfr. 28480; Mfr.

C159: Change to

@

Stock No. 0140-0081;

Part

No. 0140-0081.

@

Stock No. 0150-0079; C: fxd, 3300

Mfr. 15450; Mfr. Part No. 811-000-Y5F0332K.

Q102: Change to

Mfr.

Part

R142: Change to

Mfr. 01121;

@

Stock No. 1851-0036; Transistor: special 2N1310; Mfr. 28480;

No. 1851-0036.

@

Stock No. 0686-4735; R: fxd, comp, 47K ohms, 5%, 1/2W;

Mfr.

Part

No. EB 4735.

Figure 5-29 and Section VI,

F405: Change to

@

Stock No. 2110-0067; Fuse: cartridge, 0.3 amp; Mfr. 28480;

Mfr. Part No. 2110-0067.

($3

C:

fxd, mica, 56

Stock No. 1851-0036.

pf,

18,

500VDCW;

pf,

IO%,

500vDCW;

Manual Changes Model 185B Page 7/9

Circuit

1

1,

2

1

thru 3

1

thru 4

1

thru 5

Cut out Figure A204: Change stock number to 185B65R. CR207, CR208: Delete. Q205, Q206: Delete 2N743 designation. R275: Change value to 11K ohms.

Figure 5-29,

A401: Change stock number to 185B-65s.

R469: Change value to 909 ohms.

V401:

Tables 6-1 and 6-2,

Make changes

203210222230245-

CHANGE 13 Figure 5-17,

Action

Reference

Serial or Number

430-

3

and tape in place on Figure 5-17.

Change tube type to 8228. Delete pin numbers and replace with dot

to

indicate anode.

as

follows:

Prefix

2

50-

317317-00901 thru 01000

348-

@

Stock No.

Make

Manual Changes

I

1

thru 6

I

1

thru

7

1

thru 8

1

thru 9

1

thru

10

Description

1

a

Serial

or

I

432-

I

446-

Prefix

Number Manual Changes

I

Mfr.

Make

1

thru

1

thru 12

1

thru 14

1

th~

11

13.15

Mfr

Part

.

No.

Change Change Change Add Delete

Delete

Change Change

Delete Change Change Delete Delete

Delete Delete Delete Delete Delete

Change Change Change Change Change

A201 A204 A401 c220 CR207

CR208

Q205 Q206

R201 R210 R213 R214 R215

R216 R217 R218 R219

R220

R230 R275

R277

R278 R279

185B- 19G 18

5B- 6 5R

18 5

B- 6 5s

0140-01 52

1910- 001 6

1910- 0016

1854- 0082

0767- 0009 0811-1509

2

100- 0497 0727-0060 0727-0090

0727-0047 0687- 5601 0686-3305 0686- 1005 0686-1005

0757-0843 0811- 1507 0757-0442 0698-3476 0757-0283

Assy: Switch, TIME SCALE MAGNIFIER Assy: Etched circuit, TIME BASE Assy: Etched circuit, C: fxd, mica,lOOO pf, 5%, 300 vdcw

LV

POWER SUPPLY

---

Transistor: Silicon, NPN

---

R

fxd,

ww,

R; var,

27Kohms,

ww,

500 ohms, 10% 5w

176,

7w

---

R: fxd, mefflm, 15.OK ohms,

R: fxd, R: fxd, mefflm, 10. OK ohms, R: fxd, mefflm, 6000 ohms, R: fxd, mefflm,

ww,

11K ohms, 3%, 5w

2000

ohms,

l%,

1%

176,

1%,

1/2w

1/8w 1/8w 1/8w

DM16F102;

28 December 1965

1

thru

1

thru 4

Manual Changes Model 185B Page 8/9

Serial

Prefix

or Number Manual Changes

3

317-00901 thru 01000

348430-

Make

1

thru8

1

thru

1

thru 10

Serial Prefix Make or Number Manual Changes

1

thru

11

1

thru 12

1

thru 14

1

thru

9

13,15

1

CHANGE 13

(Cont'd)

~~

Action

Change Change

Change Change Add

Add Add Add Add Add

Add

Add Add Add Add

Add Change Change Change Change Change Change

Circuit

Reference

R280 R281 R282 R283 R288

R289 R290

R291 R292 R293

R294 R295 R296 R297 R298

R299 R414 R415 R429 R431 R469

V401

@

Stock No.

0757-0280 0757-1100 0757-0407 0757-0407 0757-0280

0757- 0273 0757- 0438 0757- 0442 0'757-0453 0757-0416

0757-0410 0757-0401 0757- 03 94 0757-0388 0683-2005

081

1

-

13

35 0812-0051 0811- 1508 0811-1337 0811-1337

07

57- 08 19

1940-0012

Description

R: fxd, metflm, 1000 ohms, R: fxd, metflm, 600 ohms, R: fxd, metflm, R: fxd, metflm, R: fxd, metflm, 1000 ohms,

R: fxd, meffln,, R: fxd, mefflm, 5.11K ohms, R: fxd, metflm, R: fxd, mefflm, R: fxd, metflm, 511 ohms,

R:fxd, metflm, 301 ohms, R: fxd, mefflm, 100 ohms, R: fxd, mefflm, 51.1 ohms, R: fxd, metflm, 30.1 ohms, R: fxd, comp, ZOohms, 5%, 1/4w

R: fxd, R: fxd, R: fxd, R: fxd,

R: fxd,

R: fxd, mefflm, 909 ohms, Tube: Electron, VR, sub-minat, type 8228

ww, ww, ww, ww, ww,

200

ohms,

200

ohms,

3.01K ohms,

10. OK ohms,

30.1K ohms,

11K ohms, 3%, 3w 15K ohms, 3%, 3w

17Kohms,

20K ohms, 5%, 3w ZOKohrns, 5%, 3w

1%, 1%, 1%,

I%,

l%,

1%,

17%

1%,

3%, 4w

17%

1/8w 1/8w 1/8w

1%,

I%,

1/8w 1/8w

1/8w

1/2W

1/8w

1/8w 1/8w 1/8w 1/8w

1/8w 1/8w

Mfr.

Part No.

CB

2005

8228/ZZlOOO

.

CHANGE 14

CHANGE 15

28 December 1965

I

i

~

Tables 6-1 and 6-2,

Q201,

Q202:

Tables 6-1 and 6-2,

Q201, Q202: Change to hp Stock No. 1853-0003; Transistor: Silicon, PNP; Mfr 28480.

Change to hp Stock No. 1853-0009; Transistor: Silicon, PNP; Mfr 28480.

Serial Prefix Make or Number Manual Changes

222-

1

thru

3

25031

-1

01

7-

000

thri.

1

1 1

thru thru thru

6

7

8

Serial Prefix Make or Number Manual Changes

1

thru

11

1

thru

12

1

thru

14

230245-

CHANGE

(Cont’d)

13

I

1 1

thru thru

4 5

348- 1

430- 1

CUT 4LONG DOTTED LINE

1-

- - - - - - - - -

CUT 4LONG DOTTED LINE

thru thru

- -

9 10

I

534-

1

thru

13 , 15

1

28

December

1965

Figure

3

I

I I

-1

I

OPERATING AND

SERVICE

MANUAL

MODEL

SERIALS

PREFIXED:.

1856

144-

OSCILLOSCOPE

Copirieht 1501

?AOE

WEWlE??-?ACKAID COHPANY

MI11

ROAD.

PA10 AllO. CALIFORNIA,

1961

U.S.A.

Table of Contents

Model

185B

TAB18

Section Page I GENERAL INFORMATION

1.1

.

Introduction

1.3

.

Options

1.6

.

Instrument Identification

1.8

.

Description

1.14

.

Cathode-Ray Tube Warranty

II

PREPARATION FOR USE

.

Incoming Inspection

2.1

2.2

.

2.4

.

2.6

.

2.8

.

2.10

.

2.12

.

Installation

.

2.13

.

2.16

2.18

.

2.20

.

Associated Equipment Available

2.22

.

Reshipment

III

OPERATINGINSTRUCTIONS

Introduction

3.1

.

Front Panel Controlsand Connectors

3.4

.

Rear PanelConnectors

3.6

.

The Principle of the Sampling

3.8

.

Triggering the Model

3.13

.

3.14

.

General

3.17

3.27

3.30

3.31

3.35

3.37

IV

PRINCIPLESOFOPERATION

4-

4.4

4.5

4.7

4.9

4.13

4.17

4.19

4.21

4.23

4.26

4.31

4.32

4.34

4.36

Triggering Methods

.

Effects of FM and Jitter

.

Pulse

.

Observation of Intermittent Pulses

.

Examining Pulse Irregularities

.

Operating Instructions

1

.

Introduction

.

BlockDiagram Description

.

General

.

Input Circuits

.

Ramp-GateGenerator

.

Time-Base Circuits

.

Calibrator

.

Vertical Amplifier

.

Horizontal Amplifier

.

Time.BaseDetermination

.

TunnelDiode Operation

.

Triggering Circuits

.

General

.

Trigger Input

.

Ramp-Gate Generator Circuits

.............

MechanicalInspection Power Requirements 230-Volt Operation Three-Conductor Power Cable Operational Check

Cooling Cabinet Mount

Rack Mount

Oscilloscope

Electronic Switch

............

Analysis

............

........

...........

.....

...........

....

........

.....

......

.......

...........

.........

..........

...........

..........

...........

.........

...........

.........

......

185B

....

......

....

.....

......

arid

.......

......

.....

......

.......

.

. .

.

OF

1-1

1-1 1-1

1-3 2-1

2-1 2-1 2-1 2-1 2-1 2-1 2-1

2-1 2-1

2-1 2-2 2-2

3-1 3-1 3-1 3-3

3 -4 3-4 3-4 3-5 3-6 3-6 3-6 3-6 3-6

4-1 4-1 4-1

4-1 4-1

4-1 4-1 4-2

4 -2 4-2 4-2 4-2 4-3 4-3 4-3 4-4

CONTENTS

Section Page

IV PRINCIPLES OF OPERATION (Cont'd)

4.46

.

Ramp-Gate Extender

Voltage Generator Circuits

4.54

.

Time-Base Circuits

4.56

.

Comparator

.

4.66

4.71

4.77

4.81

4.87

4.95

4.96

4.101

4-103.High-Voltage

4.106

V

MAINTENANCE

5.1

5.3

5.5

5.6

5.8

5.10 5- 12

5.15

5.17 5 . 30

5.31

5.34

5.37

5.41

5.43

5.45

5.47

5.51

5.53

5.57

5.59

5.67

5.68

5.69

5.70

5.72

5.73

5.75

VI

REPLACEABLE PARTS

6.1

6.4

Time Scale/Time Scale

Relationship

.

Delay Circuits

.

Comparator Blocking Oscillator

.

Horizontal-Scancircuits

.

Calibrator

.

Vertical Amplifier

.

General Operation

.

Transients

.

Low-Voltage Power Supplies

.

Introduction

.

Test InstrumentsRequired

.

Periodic

.

Cleaning

.

General Maintenance

.

Cabinet Removal

.

Troubleshooting

.

System Troubleshooting

.

SectionalTroubleshooting

.

Repair

Access

.

and Fan Motor

.

Replacement of Semiconductors

.

Servicing Etched Circuit Boards

.

CRT Replacement Adjustment Following Repair

. .

Adjustments

Low-Voltage

.

High-Voltage

.

Vertical Amplifier

.

Sync Circuit

.

Time Base

.

Performance Check

.

Time Calibrator

.

Sync Pulse

.

Amplitude Calibrator

.

Time Scale

.

Minimum Delay

.

Trigger Sensitivity

.

Introduction

.

Ordering Information

..........

.............

..........

Plower

............

...........

Maintenance

the

Air

.............

to Power Transistors

..........

Power

..........

...........

..........

...........

and

Ramp-

.......

.........

Magnifier

.........

.....

........

.......

Supply

....

...

....

.......

Filter

.....

......

........

.........

....

........

......

...

'Supplies

Supply

...

.......

........

......

........

.......

.........

.......

.

4-6 4-7 4-7

4-8 4-9 4-9 4-10 4-12 4-12 4-12

4-13 4-13

4-13

5-1 5-1 5-1

5-1

5-4

5-5

5-5 5-6 5-6 5-6 5-7

5-7

5.16

5-10

6-1 6-1 6-1

~

ii

01255-1

Model

185B

LIST

Of

ILLUSTRATIONS

List

of

List of Tables

Illustrations

Number Title Page

1.1

.

1.2

2.1

2.2

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

3.10

3.11

3.12

3.13

3.14

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

4.10

4.11

4.12

Model

.

Cathode-Ray Tube Warranty

.

Associated

.

Dimensions for

.

Operating Controls and Connectors

.

Rear Panel Controls

.

Viewing Signals Above

.

Viewing Signals Below

.

Viewing Signals Below

.

Viewing Signals Below

.

Free Running Trace

.

Unmagnified Trace

.

Magnified Trace

.

Viewing Delayed Signal

.

Using Delayed Trigger

.

Delayed Sync Pulse

.

External Scan

.

Recording the Signal

.

Overall BlockDiagram

.

Time-Base Determination

.

Tunnel-Diode Operation

.

Triggering-Circuit Block Diagram

.

Tunnel-Diode Count-Down Circuit Ramp Generator

. .

Time-Base BlockDiagram

.

Ramp Voltage vs Time

.

Effects of Delay

.

Staircase Generator

.

Vertical Amplifier Block Diagram

.

High-Voltage Power Supply

185B

Oscilloscope

Dual-Trace Vertical Plug-In

($9

Equipment Available

Rear

with

Support

.........

10

kc

10

kc by Using

Delayed Trigger

SYWC

PULSE OUT

Circuit under Test

Block Diagram

...........

10

kc by Using

..........

10

kc when the

..........

.........

..........

...........

........

..........

............

.........

.....

....

........

.....

........

......

.......

Model

187B

Unit

.

1-0

......

...

.....

...

......

...

1-3

2-0 2-3

3-0 3-2 3-5

3-5 3-5

3-5 3-7 3-8 3-9 3-10 3-11 3-12 3-13 3-13

4-0

4-2 4-3

4-4

4-5 4-6 4-8 4-a 4-10 4-11

4-13 4-13

Number Title Page

5.1

.

Driving the Trigger Circuit

.

Trigger Circuit Waveforms

5.2

Disassembly for Power Transistor

.

5.3

Replacement

.

MinimumDelay Measurement

5.4

5.5

.

Calibrator Instrument Setup

.

Top View, Model

5.6

5.7

.

Left Side

5.8

.

Right Side View, Model

5.9

.

Bottom View, Model

.

5.10 5 .ll

5.13

5.14

5.15

5.16

5.17

5.18

5.19

5.20

5.21

5.22 . A602

5.23

5.24 5-25

5.26

5.27

5.28

5.29 5 .30

5.31

5.32 . A302

5.33

A103

.

Waveforms

5.12

.

Parts Location, Switch Assemblies

.

Trigger Circuit, Schematic Diagram

.

A204

.

Waveforms

.

Parts Location, Switch Assemblies

.

Time-Base Circuit, Schematic Diagram

.

A1

.

Waveforms

.

Assembly Location

.

Main Vertical Amplifier,

Schematic Diagram

.

Waveforms

.

Assembly Location

.

Parts Location, Calibrator and Sync Pulse

Switch,

.

Calibrator and Sync Pulse Generator,

Schematic Diagram

.

A401

.

Assembly Location

.

Low-Voltage Power Supply,

Schematic Diagram

.

A301

.

Assembly Location

.

High-Voltage Power Supply,

Schematic Diagram

View,

Component Location

and

A2

Component Location

S601,

and

A402

Component Location High-Voltage Rectifier Assembly

............

185B

Model

185B

.............

..........

.............

..........

with Amp1 . Conn

.........

Component Location

..........

.........

..........

......

.....

......

........

185B

......

185B

......

.......

...

.

.......

...

.....

........

.......

.

5603 . 5-23

.

.......

.

........

5-3 5-3

5-5 5-8 5-8 5-11 5-12 5-12 5-13 5-16 5 . 16 5-17 5-17 5-18 5-18 5-18 5-19 5-20 5-20 5-21

5-21 5-22 5-22 5-23

5-23 5-24 5-24

5-25 5-26 5-26 5-26

5-27

LIST

Number Title Page

1.1

.

Specifications

2.1

.

Associated Equipment Available

.

3.1

5.1

5.2

5.3

5.4

01255-1

Methods of Triggering

.

Recommended Test Equipment

.

System Troubleshooting

.

Resistance to Ground

.

Adjustments Following Tube, Transistor,

and

Diode Replacement

............

....

........

.....

........

.........

.......

1-1 2-2 3-4 5-0 5-2 5-4

5-6

Of

TABLES

Number Title Page

5.5

.

Time Scale Adjustments

5.6

.

Condensed Test and Adjustment

Procedure

5.7

.

Amplitude Calibrator Accuracy

.

Time Scale Calibration Check

5.8

6.1

.

Reference DesignationIndex

.

Replaceable Parts

6.2

.............

.......

....

.....

..........

5-8 5-9

5-10 5-10

6-2 6-24

iii

Section

Figure

I

1-1

Model

185B

Y

Figure 1-1. Model 185B Oscilloscope with Model 187B Dual-Trace Vertical Plug-In Unit

1-0

~

01255-1

Model

185B

Paragraphs

Section I

1-1

to

1-10

SECTION

GENERAL INFORMATION

1-1.

INTRODUCTION.

1-2.

This manual gives operation and maintenance

information for the An operational check operation performance check specifications during incoming inspection paragraph

1-3.

1-4.

P2

phosphor with external graticule.

options, however, are available:

a.

b. Option c. Option

d:

e.

1-5.

option

differences in crt persistence, color, and oscilloscope photography techniques, instruments with or without option are, however,

(see section VI).

in this manual apply to all options unless otherwise indicated.

is

given in paragraph

5-67.

OPTIONS.

The

Model

Option

Option Option

1.

P1

Internal graticule in cathode ray

3.

7.

P7 phosphor

11.

P11

31.

P31 phosphor

Option

31

1

is

available only with option

3

are operationally interchangeable. There

some differences in component parts

@

Model

to

185B

assure basic instrument

2-10.

that

may be used for verifying

185B

is

normally supplied with

phosphor

is

not available with option

All

references to the Model

Oscilloscope.

A

complete

is

given in

The following

tube

3,

3.

Other than

and

185B

I

1-6.

INSTRUMENT IDENTIFICATION.

1-7.

Hewlett-Packard Company uses a two-section

eight-digit serial number (e.g.

first

three digits of the serial number onyour instru-

ment are not

with

this manual which define differences between

your instrument and

sheets are missing, your Hewlett-Packard engineering representative can supply you with the necessary information.

144-,

change sheets have been supplied

this

a

1-8.

DCSCRl?TlON.

1-9.

GENERAL. The

provides

ena

will

below

spaced. signal

operate reliably.

above obtain jitter-free presentation.

1-10.

high speed characteristics nique. Using this system the entire signal under examination taken on different occurrences of the input at slightly later points along the waveform.

a

with repetition rates to

visual display of very high-speed phenom-

present a steady display of pulse repetition rates

100

kc even when the signals are randomly

For frequencies above

is

divided down

100

kc, more uniform spacing

PRESENTATION. The Model

is

scanned, with each succeeding sample

@

Model

so

that the input circuitry will

As

the input frequency increases

by

000-00000).

manual. If

1000

mc. The instrument

100

185B

kc,

is

these

Oscilloscope

the

185B

using the sampling tech-

Each time such a

If the

change

incoming

required

obtains

to

it8

I

HORIZONTAL

Sweep Speeds:

10 ranges, within between ranges and increases fastestunmaanified sweep speedto sweep the exception of time represented by

of

the unmagnified sweep.

Magnification:

7

calibrated ranges

and

X100.

speed to sweep speed

Intensity and sample density are not affected by

magnification.

Delay Control:

Three-turn when using magnified sweep. Permits any tion of unmagnified trace

10

nsec/cm

Vernier gives continuous adjustment

&5%.

4

is

maintained at all magnifier settings with

Increases maximum calibrated sweep

0.1

nsec/cm; with vernier, maximum

is

further extended to

variable delay control

to

10

psec/cm, accuracy

nsec/cm. Accuracy of the basic

X1,

X2,

X5,

X10, X20, X50,

0.04

is

to

be

viewed on screen.

01255-1

Table

first

nsec/cm.

available

1/4

por-

1-1.

Specifications

cm

Minimum Delay (input trigger

Less than faster. On slower sweep

lay increases to

5

psec on the lO-psec/cm range.

Sample

Continuously adjustable from approximately 70 samples per trace

Scanning Functions:

Internal

for normal viewing.

Record

approximately

Manual

knob.

External

approximately input impedance greater than

120

Density:

-

X

-

X

-

X

-

nsec at

a

maximum of approximately

to

axis

driven

axis driven by internal slow ramp;

60

seconds for one trace.

axis driven by manual scan control

X

axis

driven

12

volts for 10-cm deflection,

to

start

100

nsec/cm sweep and

speeds,

1000

by

minimum de-

samples per trace.

internal staircase

external voltage;

25,000

Specifications cont'd

of trace):

ohms.

1-1

Section

Table

I

1-1

(cont‘d)

1-1.

Table

“RIGGER FUNCTIONS Normal-External Trigger

to

Amplitude: 450 mv

volts rms or 100 volts peak will not damage input circuit.

Width: 5 nsec at minimum amplitude.

Rate:

50 cps to 1 mc speed setting. Maximum 100 mc on the 200 nsec/cm

Jitter:

Input Impedance: 50 ohms nominal

Sensitive-External Trigger

Amplitude: *15

Width:

Rate: Same as normal

Jitter:

Input Impedance: 50

High Frequency

Input Frequency: 50 to Sensitivity: 200 mvpeak-to-peak. Operates from

Jitter: 4% of cycle from 50 to 400 mc;

Signal at Input Connector: Less than 15 mvpeak-

Input Impedance: 50 ohms nominal, ac coupled.

SYNC PROBE The 185B-21A (use with any trigger function) in-

creases input impedance to more than 7500 ac coupled; reduces sensitivity by approximately 4:l at 10 mc and higher and by approximately 20:l

at

low frequencies.

SYNC PULSE OUTPUT Amplitude: Positive; at least 1.5 v into 50 ohms Rise Time: Less than 2 nsec Width: Approximately 5 psec Recurrence: One pulse per sample

CALIBRATOR Voltage:

20 mv, 100 mv,

Time:

Approximately 5 psec burst of 50 mc sinewave.

Frequency accuracy

Less than 0.03 nsec or 0.02% of the time represented ever

is

approximately 5:l in the “smoothed” response position.

Reflection from step of

by

greater (fast rise Signals). Reduced

to

rms or 10 volts peak circuit.

5 nsec at minimum amplitude

Same as normal

of 200 nsec/cm smaller signals at some increase in jitter. Up

to 5 volts rms or 15 volts peak will not damage input circuit.

from 400 to 1000 mc to-peak, approximately 10 mc Reflection from step of

less than 8%.

i2 volts peak. Up

on

the lO-Fsec/cm sweep

rate

increases

and

faster

the

unmagnified speed, which-

1/2

nsec

is

*200 mv peak. Up to 5 volts

will

not damage input

ohms

nominal, dc coupled

1000

mc forsweepspeeds

and

faster

1/2

nsec rise time

200

mv, and 1000 mv;

dc

less

8%

rangee.

coupled. than

of Cycle

*2%.

Specifications (cont’d)

X-Y

RECORDER OUTPUT

X-

and

to

5

to

8%.

is

ohms,

&

minals in all positions of the scanning control. In the

MANUAL and RECORD positions the voltage

can

be

ventional

Horizontal Output: Approximately

of sweep v/cm).

Vertical Output: Approximately

graticule, impedance approximately 1,000 ohms.

GENERAL Cathode Ray

5AQ mono accelerator with P2 phosphor normally supplied. 2900-volt accelerating potential,

External Graticule (standard):

Edge lighted with controlled illumination, 10 cm

by

axes have 2-millimeter subdivisions.

Power: 115 or 230 volts

approximately

Dimensions:

Cabinet Mount: 14-5/8 inches high, 19 inches

wide, 22-1/8 inches deep

Rack Mount: 12-1/4 inches high, 19 inches

wide, 21 inches deep behind panel

Weight:

Cabinet Mount: Net 65 lb Accessories Furnished: 185B-21A Sync Probe Accessories Available:

185A-39A Plug-In Extender

185A-21C Resistive Divider Probe, 5:l division,

185A-21D Resistive Divider Probe,

185A-21E Resistive Divider Probe, 50:l divi-

185A-21F Resistive Divider Probe,

AC-16W 3-ft RG-55 cable for 185A-21C,D,E,F

Associated Instruments:

187B Dual Trace Vertical Amplifier

187B accessories available:

187A-76A BNC Adapter 187A-76B Type 187B-76C 10: 187A-76D Blocking Capacitor 187B-76E 50-ohm T Connector Model Model 908A 50-ohm Coaxial Termination 187B-76F Adapters 187B-76G Probe Socket

Model 213A Pulse Generator,

Model 185B

Y-axis

used to make pen recordings with a con-

signals are available at rear

X-Y

recorder.

to

+13 volts at end of sweep (1.2

Source

impedance approx. 20,000 ohms.

-1

volt at bottom (0.2 v/cm), Source

0

volt

+1

volt at top of

at

ter-

start

Tube:

P1,

P7, and

10 cm, marked in centimeter squares. Major

300

250 ohms

sion, 500 ohms

sion, 2500 ohms sion, 5000 ohms

llOOA

nsec

rise

time k350 mv amplitude

P11

watts

N

Adapter

1

Divider

Delay Line

phosphors available.

*IO%,

50 to

less

60

1O:l

divi-

1OO:l

divi-

than 0.5

cp8,

A.

1-2

01255-1

Model

185B

Paragraphs

Section I

1-11

to

1-15

sample

is

taken, the

“spot"

on the

crtis

moved hori-

zontally along the waveform. Thus, a complete pic-

ture of

a

repetitive high speed signal

is

synthesized by a buildup of image-retaining “dots” on the oscilloscope face

1-11.

The Model ranging from nanoseconds per centimeter depending on the of the TIME SCALE switch. Any part time scale can by adjusting the TIME SCALE MAGNIFIER

as

a graph

185B

10

microseconds per centimeter

be

expanded without loss

is

provides

plotted point by point,

10

basic

time

scales

setting

of

this

of

calibration,

switch.

to

10

basic

Built-in time and amplitude calibrators provide a convenient means vertical calibration. Intensity of pendent of duty cycle, and vertical deflection may adjusted up

185B

to

provides output signals for

of

checking

10

centimeters. In addition, the Model

both

horizontal and

the

trace

X-Y

recorders and

is

inde-

be

provides means for controlling the display either manually or externally.

1-12.

VERTICAL AMPLIFIER. The vertical system

of the Model

such as the Model

185B

includes aplug-in vertical amplifier

187B.

It

is

this amplifier which determines vertical characteristics such as bandpass, sensitivity, etc. The vertical plug-in unit

of

the

basic

1-13.

F’igure

185B-21A

Model

Sync Probe shown in

185B

Oscilloscope.

1-1

illustrates the Model

the

figure with the oscilloscope. The Model Vertical Amplifier plug-in unit

Table

1-1

1-14.

CATWODLRAY

1-15.

The cathode-ray tube supplied with the Model

185B

is

lists

guaranteed against electrical failure for one year from the date Company. The cathode-ray trated in figure in the appendix of

is

shown installed, although the

not part of the basic oscilloscope.

the specifications for the Model

TUBE

WARRANTY.

of

sale

by

the

tube

warranty

1-2.

A

sheet

for your use

this

manual.

is

not part

187B

185B.

is

Dual Trace

The

supplied

185B.

Hewlett-Packard

is

illus-

is

included

IEWLETT-PACKARD

01255-1

CO.

PAOC

MILL

ROAD.

PAL0

Figure

ALTO. CALIF.

1-2.

U.S.A.

Cathode-Ray

Tube

Warranty

1-3

se~tian

Figure

n

2-1

Model

185B

MODEL DUAL TRACE

I

CAL AMPL I F I ER

VERT

1878

MODEL 196A/B

OSCILLOSCOPE

CAMERA

MODEL IlOOA

DELAY LINE

MODEL DELAY

2-0

I

00A-76

LINE LOAD

A

Figure

2-1.

CONNECTING

Aellociated

@

Equipment

Available

MODEL l85A-76A SYNC TAKE-OFF

UP

-Y-93

01255-1

Model 185B

Section

Paragraphs 2-1

to

II

2-19

SECTION

PREPARATION

2-1.

INCOMING INSPLCTION.

2-2. MECHANICAL INSPECTION. 2-3. Upon receipt of your Model 185B, check the

contents against the packing strument for any obvious damage received in transit.

If

damage

(Refer ditional information.) all re-usable packing material until an operational

check

2-4. POWER REQUIREMENTS.

2-5. The Model 185B requires

115 or 230 volts which can deliver approximately

2-6. 230-VOLT OPERATION.

2-7. operated switch ment. The existing fuse should

2-ampere slow-blow fuse.

Be erly for the line voltage power supplies may switch

2-8. THREE-CONDUCTOR POWER CABLE, 2-9. To protect operating personnel, the National

Electrical Manufacturers' Association (NEMA) ommends grounded. This instrument conductor power cable which, when plugged into an appropriate receptacle, grounds the instrument. The offset pin on the power cable three-prong connector

is

the ground pin. To preserve the protection feature when operating the instrument from outlet, use connect the green pigtail to ground.

2-10. OPERATIONAL CHECK. 2-11. The following procedure

for checking basic operation controls mentioned in the following procedure shown in figure 3-1. A complete check-out procedure

to

verify specifications

a.

Install the vertical plug-in unit.

gain

to

b.

Turn INTENSITY

c.

Set

100 NSEC/CM,

is

evident, file claim with the carrier.

to

the

warranty sheet in

To

has

been successfully completed.

*lo%,

If

.230-volt operation

is

provided on the rear of the instru-

CAUTION

sure

to

set

the 115-230 volt switch prop-

is

set

to the wrong position.

that

the instrument panel and cabinet

a

three-prong to two-prong adapter and

approximately 50 mv/cm.

full

SCANNING to INTERNAL, TIME SCALE to

DENSITY full clockwise, MODE

list

and inspect the in-

this

facilitate reshipment, keep

single phase,

is

desired, a screwdriver-

be

is

equipped with a three-

of

is

given in paragraph 5-67.

counterclockwise.

manual for ad-

a

power

300

be

to

be

damaged

is

given

the Model 185B. All

source

50

to

watts.

replaced with

used. The

a

60 cps,

if

this

two-contact

as

a

means

Set

vertical

of

rec-

be

are

to

II

FOR

FREE RUN, TIME SCALE MAGNIFIER and CALIBRATOR AND SYNC PULSE OUTPUT switches full counterclockwise.

d. Center HORIZONTAL POSITION and VERTICAL

POSITION controls.

e.

minutes

vertical plug-in input

f.

pears.

and readjust HORIZONTAL POSITION and VERTICAL POSITION controls as necessary.

g.

h

mately five cycles of

2-12.

a

2-13. COOLING.

2-14. The Model 185B uses tem within the cabinet. The air intake and filter cated on ment, choose of clearance around rear and sides of cabinet..

2-15. the

be

coated with a

No.

filter

cooling. Refer to paragraph

procedures.

2-16. CABINET MOUNT. 2-17. The Model 185B cabinet mount

instrument. ated with plane.

ment to a better viewing angle. Be sure to maintain clearance required for proper cooling mentioned in

paragraph 2-14.

2-18. RACK MOUNT. 2-19. The standard rack model

rear-support pins and bushings. The bushings installed on rear flanges. The pins are for use in mounting the instrument tended to mate with bushings when instrument stalled. Do not mount the instrument with only frontpanel screws, particularly

to

any

support pins securing front panel to rack are not supplied. Install instrument

USE

Turn the Model 185B on and allow about

for

the instrument

to

Rotate INTENSITY clockwise until a

If

the crt remains

Adjust FOCUS for a

resultant presentation should

The

a

INSTALLATION.

to

maintain tolerable operating temperatures

rear

of instrument. When mounting instru-

a

site

that provides

AIR

air

FILTER. Before operating the Model 185B,

filter,

3

from Research Products Co. In addition, the

should

A

vibration or shock.

located at rear of instrument, should

filter

be

cleaned periodically to insure proper

The instrument

its

front panel in a verticalor near-vertical

bail

is

provided for raising front of instru-

are

shown in figure 2-2. Screws for

as

follows:

to

the 50-mc connector.

50-mc sine wave.

adhesive such

stabilize. Connect the

blank,

press BEAM FINDER

thin,

well-defined

a

forced-air cooling

at

least three inches

as

5-6

for proper cleaning

be

is

intended

is

at

installation and are in-

if

installation

Location dimensions for

to

supplied with

trace

approxi-

Filter

a

portable

be

is

two

ap-

trace.

sys-

are

lo-

Coat

oper-

two are

is

in-

subject

01255-1

2-

1

Section Paragraphs

II

2-20

to

Model 185B

2-23

(9-1

196A/B

Oscilloscope Camera

187B

Dual

Trace Amplifier

1

lOOA

Delay

Line

Sync Take-Off

11OOA-76A

Delay Line

Resistive Dividers

185A-21C 185A-21D 185A-21E 185A-21F

AC-16W

Cable

Load

Use

A

High quality camera for use in permanently recording oscilloscope presentations

~~ ~~

A dual-channel vertical amplifier

(plug-in) for Model 185B (shown installed in figure

Overcomes inherent oscilloscope delay,

allowing

rate

Inserted

line

sumdied

~~

Termination for

(normally suppliedwith Model system)

~

These dividers provide a means for

obtaining

capacitance input

Delay

(All

cable terminated in 50 ohms)

Connecting

Dividers

rise

pulses

to

between

permit sync

with

a

high-impedance, low-

Line

or other 50-Ohm systems.

dividers must

cable

1-1)

times of slow repetition

be

viewed

signal

Model

llOOA

for 185A-21C/F

line

take-off

llOOA

Delay Line

to

Model llOOA

be

used with

and delay

(normally

system)

llOOA

Features

Image

to

object ratio:

(1:

1

available)

Model 196B allows oscilloscope

photograph on either internal

external

I

Sensitivity 4 mv/cm Badwidth:

1000 mc

Input

2 pf nominal

Rise Time: 0.25

Delay:

Insertion

6

db for both

Termination Resistance: 50

graticule oscilloscopes

DC

to

Impedance:

120

ne

Loss:

channels

l:O.

9

to

200 mv/cm

800mc ueable

lOOK shunted

M

ohma

or

1

to

by

c

3

Division

Input Res.

250 5:

a

500

2500 50:

5000

Ratio

10:

100:

Max

Inpl

VRMS

1

1 1

10 15

35

50

J

186A

Switching Time Tester

I

a.

Fabricate a bracket for rear support pins and

fasten pins

b.

c.

port

2-20.

2-21.

is

available from Hewlett-Packard Company crease the usefulness of your Model 185B. Additional equipment in unit. Refer to the manual for operating information regarding your particular plug-in or contact your nearest

this

information.

2-2

in

place.

Install

Lift instrument into place, engaging rear-sup-

pins, and secure front panel firmly to rack.

bracket at

ASSOCIATED EQUIPMENT

Figure

2-1 and

is

available for use with the vertical plug-

@

representative and he

rear

table

Measures switching time of transistors,

diodes and tunnel diodes. Teste pulse

response of active and passive net-

works. Triggers Model 185B in

vance of pulse output. Accessory universal adapter available.

of rack.

AVAILABLE.

2-1 show equipment

will

supply you with

to

that

in-

to

Pulse output: 0.1 Pulse Rise Time: Pulse Repetition

ad-

2-22.

2-23. dent, repack the instrument using the following procedure

shipping container, taking in their original positions. (If was discarded, more may Hewle

able,

RESHIPMENT.

If,

after

as

a

a.

If

possible, repack the Model 185B in

tt-

Packard Engine e r ing Representative.)

b.

If

the original packaging material

proceed as follows: (1) Wrap instrument in heavy paper or plastic. (2)

Use around panel

continuously variable

Collector Supply:

Base

Supply:

I

incoming inspection, damage

guide.

care

be

plenty of packing

all

sides of instrument and protect

with

cardboard strips.

material

20 volts peak

LRss

than 1 nsec

Rate:

5 kc

to

50 kc,

0

to

*SO volts

0

to

+lo

volts

is

its

(at

is

least

original

all

material

not avail-

01255-1

to

replace

the

packing

obtained from your

evi-

pads

4

in.)

I

Model

185B

(3)

Place

cardboard

or metal

(4)

Mark the Instrument”,

instrument thus protected

or wooden

bands

to

packing

seal

box

box,

container.

with

‘‘

Fragile”,

and use heavy tape

etc.

Note

If

instrument Packard Company for service or repair, attach type of service or repair

correspondence, model number

serial number.

a

is

to

be

shipped

tag

identifying owner and indicating

refer

and

to instrument by

complete eight-digit

to

desired.

in a heavy

“Delicate

Hewlett-

In

any

REAR

OF

INSTRUMENT

Figure

Paragraph

Dimensions for Rear Support

2-2.

Section

2-23

II

Cmt’d

01255-1

2-3

Section

Figure

111

3-1

Model 185B

1.

Power switch. Energizes instrument.

2. INTENSITY. Adjusts brilliance of spot on the cathode-ray

3.

SCALE. Adjusts with graticule on option 3 instruments.)

4.

FOCUS. Adjusts focus of spot on the cathoderay

tube.

5. BEAM FINDER. Helps locate a presentation

that

is

6.

SCANNING. Adjusts mode of horizontal deflection.

7. SCAN (MANUAL) or DENSITY (INTERNAL).

Used

to

density.

8. TIME SCALE. Adjusts basic time scale of presentation.

9.

VERNIER. Provides continuously variable time scale between TIME SCALE ranges.

10.

TIME SCALE MAGNIFIER. Expands time

scale

11.

DELAY. Enables operator magnified presentation.

12. HORIZONTAL POSITION. Adjusts horizontal

positioning of presentation.

tube.

scale

brilliance. (Aligns trace

deflected

manually scan display or

off

selected

the

crt.

by

TIME SCALE control.

to

adjust scan

the

basic

view any part of

13.

INPUT. Connection for trigger input. Sensitivity: SENSITIVE i200 mv; NORMAL i200 mv to 2 volts.

14.

STABILITY. Adjusts trigger stability.

15. MODE. Adjusts trigger sensitivity. May

set

to

FREE RUN.

16. TRIGGER SLOPE. Selects desired trigger slope polarity.

17.TRIGGERING. Set frequency and amplitude

18. HIGH FREQUENCY STABILITY. ger stability on HIGH FREQ. position of TRIGGERING.

19.Model 187B

plug-in unit. Not part of

20.SYNC. PULSE OUTPUT. Provides

sync pulse out for triggering to use as a

21.50 MC. Provides a pulsed 50-mc output.

22. AMPLITUDE DC (OPEN CLRCUIT). Provides output of four calibrated dc voltages.

23,CALIBRATOR AND SYNC PULSE. Selects

calibrated to appropriate connectors.

Dual

test

dc

this

switch according

of

trigger signal.

Adjusts

Channel Vertical Amplifier

basic

oscilloscope.

a

test

circuits, or

pulse.

voltages or sync pulse outputs

be

to

trig-

delayed

~~

Figure

3-0 01255-1

3-1.

Operating Controls and Connectors

Model 185B

Paragraphs 3-1

Section

to

111

3-5

SECTION

0

P

ERATI

3-1.

INTRODUCTION.

3-2.

This

tion of all controls in the Model 185B Oscilloscope.

If

more theoretical information

Section 3-3. The vertical amplifier system for the Model

185B includes

for operating the plug-in unit are contained in the in-

struction manual for

3-4.

3-5. Figure 3-1 shows

trols and gives a short description of theiruse. Num-

bers

ure

3-1

dicate operational procedure. More detailed information related to

a. BEAM FINDER. Pressing the BEAM FINDER reduces gain of horizontal and vertical amplifiers to a point where a “lost” presentation may adjusted HORIZONTAL POSITION and VERTICAL POSITION controls.

b. SCALE. The SCALE control adjusts intensity of graticule on those instruments provided withanexternal graticule. On internal graticule instruments, SCALE aligns trace with graticule.

c. INPUT. This connector chronizing circuits. These circuits insure an exact time relationship between input signal and moment of sampling. To operate properly, the sampling oscilloscope nal that supply step

i).

d. TRIGGERING. The TRIGGERING switch may

be

set to SENSITIVE, NORMAL or HIGH FREQ.

pending on amplitude and frequency of trigger signal.

SENSITIVE position 200 millivolts with a frequency below 100 mc. Do not exceed 10 volts peak input on SENSITIVE position. NORMAL position nals (200 mv to position should be used for trigger signals of

plitudes above 100 mc. The input circuits on HIGH

FREQ. position 1000 mc circuits.

Do

peak to INPUT when TRIGGERING SITIVE. Doing

section contains information on the func-

is

desired, refer

IV,

Principles of Operation.

a

plug-in unit. Detailed instructions

that

particular unit.

FRONT PANEL CONTROLS AND

CONNECTORS.

all

front panel operatingcon-

in figure 3-1 are given

to the photograph and do not necessarily in-

these

to

center of cathode-ray tube using the

either

must

be

is

time-related to the input signal, or must

a

sync pulse to trigger circuit under

is

2

volts) below 100 mc. HIGH FREQ.

will

so

they may

not connect any voltage exceeding 10 volts

divide down signals

be

CAUTION

so

may damage inputcircuits.

to

relate the

controls

is

accurately triggered by a sig-

used for trigger signals below

used for higher amplitude sig-

used

to

is

listed

be

the input

operate synchronizing

is

on SEN-

N G I

text

in fig-

below:

found and

to

the syn-

test

all

as

high as

to

(see

de-

am-

111

NSTRU

adjusts frequency of count-down oscillator, enabling

it

either positive-going or negative-going slope signal.

of input circuits same point on input signal.

full

sync circuits will at a 100-kc rate. quency above near 100 of the input signal.

triggering stability for repetition

by

PUT connector provides

is

With sync pulse from SYNC PULSE OUTPUT connected in Model 185B delaying input signal for the purpose of examining

fast

wave output, synchronized with pulse from SYNC PULSE OUTPUT. Frequency of sine wave cycles. This signal reference on the cathode ray tube, or for checking time

nector provides dc voltages selected by CALIBRATOR AND SYNC PULSE switch for calibration of vertical amplifier in oscilloscope. Voltages selected are accurate to within i3$~ of selected value.

when in sync pulse output and pulsed 50-mc output to appropriate jacks. On other positions of this switch, voltage CUIT) connector

mines time time calibration of fications when VERNIER control clockwise.

fine adjustment between any TIME SCALE switch, resulting in continuous variation of time scale from

CTI

0

NS

e.

HIGH FREQUENCY STABILITY. This control

to

lock

in

at a submultiple of input trigger frequency.

f.

TRIGGER SLOPE. The TRIGGER SLOPE switch

may

be

used

to

synchronize Model 185B circuits

of

g. MODE. The MODE control adjusts sensitivity

clockwise

kc

h. STABILITY. The STABILITY control adjusts

varying hold-off time in triggering circuits.

i.

SYNC

PULSE OUTPUT. The SYNC PULSE OUT-

delayed 130 nanoseconds from trigger initiation.

to

circuit under

rise

time.

MC. This connector provides

j.

50

scales

k. AMPLITUDE (DC OPEN CIRCUIT). This con-

m. CALIBRATOR AND SYNC PULSE. This switch,

full

is

supplied to AMPLITUDE (DC OPEN CIR-

n. TIME SCALE. The TIME SCALE switch deter-

p. VERNIER. The VERNIER control provides

so

they

will

trigger reliably

If

MODE control

to

FREE RUN position, Model 1858

free

run,

i.e.

sample automatically

If

they

are

triggered withafre-

100

kc,

they

will

but

will

synchronize with a submultiple

test,

is

overcome. The effect

is

valuable for setting up a time

on oscilloscope.

counterclockwise position, connects both

as

explained in step

scale

in nsec or p sec per centimeter. The

this

switch

operate

a

fast

inherent delay (0.1 psec)

is

two

IO

psec/cm to 3 nsec/cm

at

a

frequency

rates

above 100

rise

time pulse

is

similar

a

pulsed sine

is

50 mega-

k.

correct within speci-

is

full Counter-

steps selected

on

trigger

at

the

is

set

kc

that

to

a

dc

by

a

01255-1

3-1

Section

Figure

III

3-2

Model

185B

1.

Regulated dc output connector instruments.

2.

Channel A vertical output voltage deflection present on 187B). Sensitivity 0.2 volt/cm, Graticule Center:

3.

Channel B vertical

as

item

0

2.

volt.

For

output.

this

use

for

use with future

for

connector (with Model

with

X-Y

Same

characteristics

vertical

recorder.

-

4. OUTPUT TIME BASE SCAN. Horizontaldrive voltage

with

Sweep

5. INPUT EXT SCAN. Connect drive

volts/cm, Input Range:

6.

115-230 Volt Switch.

used.

volt operation, 2-ampere slow-blow fuse 230-volt operation (see section

is

available at

X-Y

recorder. Sensitivity:

Start:

0

volt.

signal

to

this

connector. Sensitivity:

0

Use

4-ampere slow-blow fuse

Set

this

connector.

external

to

12

volts.

to

line voltagebeing

VI).

1.2

volb/cm,

horizontal

for

POWER

CORD

For

use

1.2

115-

for

3-

Figure

2

3-2.

Rear-Panel Controls

01255-1

Model

185B

Paragraphs

Section

3-6

to

111

3-7

.

q.

TIME SCALE MAGNIFIER. The TIME SCALE MAGNIFIER switch selected by TIME SCALE switch by TIME SCALE MAGNIFIER switch.

r.

DELAY. The DELAY control selects any part of unmagnified presentation for magnification; with delay control you effectively slide cathode-ray tube along expanded presentation

divides

the value

by

number selected

to

view portion you

that

has

been

i.e.,

want

8.

SCANNING. The SCANNING switch determines

type

of horizontal deflection

point

it

should

beam across the face of the cathode-ray tube

relation The beam may of the tube and yet the time ample,

185B

deflection; they

to

50

provides a choice

(1)

INTERNAL. The time

setting of TIME SCALE and TIME SCALE

MAGNIFIER switches. On INTERNAL, the beam of the tube DENSITY control and sampling frequency.

(2)

MANUAL. On MANUAL position, scanning

accomplished DENSITY (INTERNAL) control. Manual operation may sweep the only visible portion of trace illuminated by setting of MANUAL SCAN control. The time scale in seconds per centimeter

is

determined again

MAGNIF'IER and TIME SCALE switches. Man-

ual scan

it

is

e.g., when RECORD. On RECORD position, operation

exactly the same as on MANUAL except in very slowly across time scale determined by setting SCALE MAGNIFIER and TIME SCALE switches.

RESET OR EXTERNAL. The RESET OR EXTERNAL position

vides a means for resetting scan when oper-

ating on RECORD position,

a

means of scanning with an external signal.

An input connector, INPUT EXTERNAL SCAN,

is

horizontal input,

t.

SCAN (MANUAL) - DENSITY (INTERNAL), The function of this control depends on setting of SCANNING switch. NAL, the SCAN (MANUAL)

control adjusts number of samples per centimeter and hence the density of sample dots viewer. Reducing scan density ing up the physical speed of horizontal sweep,

be

emphasized

its

time scale in seconds per centimeter.

take

10

nanoseconds per centimeter. The

are

as

is

automatically swept across the face

at

an actual speed determined

by

be

thought of as a condition where

is

always present on oscilloscope, but

is

useful in

necessary

fast

spikes are present on waveform.

this

case the beam

provided on rear of instrument for external

With

SCANNING switch

that

will

be

used.

At

that

apparent speed of

has

seconds to go across the face

scale

could

be,

for ex-

Model

of

four

follows:

adjusting SCAN -(MANUAL)

to

carefully trace presentation,

has

modes of horizontal

scale

is

determined

is

that

by

setting of TIME SCALE

x-Y

recorder work when

is

automatically swept

the

face of the tube

of

two

functions:

or

-

DENSITY (INTERNAL)

has

the effect of speed-

1)

2)

it

provides

set

to

INTER-

as

seen by the

TIME

it

this

no

by

is

part

is

that at

pro-

i.e.,

-

a

the actual speed oscilloscope face. However, turning

no effect on time scale in seconds per centimeter on

cathode-ray tube. On the MANUAL position of the SCANNING switch, the SCAN (MANUAL) (INTERNAL) control moves dot along presentation explained in step EXTERNAL positions of SCANNING, the SCAN

UAL) - DENSITY (INTERNAL) control

3-6.

REAR PANEL CONNECTORS.

3-7.

Figure

and gives a short description of their uses.

figure

the figure to the photograph and do not necessarily indicate operational procedure. The following paragraphs give more detailed information about

connectors:

nector

sory instruments. The following voltages

able with reference to ground (pin

Channel terminals for use in driving an the Model nector

0

(0.2

20,000

Channel terminals. Output characteristics of CHAN B are identical

scan voltage available at this connector to drive horizontal of X-Y recorder. The output from OUTPUT TIME BASE SCAN and Source impedance

means of controlling scan with an external signal. The scan voltages required supplied by OUTPUT TIME BASE SCAN connectors, i.e., about HORIZONTAL POSITION centered). Input resistance varies with setting minimum

connects Model voltage setting selected.

fuse

3-1,

a.

5401,

is

intended

1)

Pin b,

2)

Pin c,

3)

Pin d,

4)

e,

b.

OUTPUT CHAN

A

is

approximately

volt in center, and

volt/cm). Source impedance

ohms.

c.

OUTPUT CHAN

B

to

d. OUTPUT TIME BASE SCAN. The horizontal

+12

volts

e.

INPUT EXT SCAN. This connector provides

0

volt

+13

is

f.

115-230

(see

section VI).

to

produce one complete picture on

this

control

-

has

DENSITY

as

s(2).

On RECORD and RESET

3-2

shows

all

connectors on

the numbers in figure

is

3-2

inoperative.

rear

relate

OR

(MAN-

panel

As

in

text

in

these

regulated dc output connector. This con-

to

supply

dc

power tofuture acces-

are

avail-

a):

+12.6

volts

-12.6

volts

+250

volts

-100

volts

A.

The vertical output from

of the plug-in unit

187B

installed. The output from this con-

+1

-1

B.

of the plug-in unit

those of CHAN

that

has been selected

is

approximately 0 volt at sweep

at

sweep termination

is

approximately

is

available at these

X-Y

recorder with

volt at top of graticule,

volt at bottom of graticule

is

approximately

The vertical output from

is

available

A.

by

at

these

SCANNING

is

axis

start

(1.2

volts/cm).

20,000

ohms.

a

are

the same

to

position scan at left edge of crt, and

volts to position scan at right edge (with

of

time scale VERNIER

32.3K.

volt switch. This switch automatically

185B

power transformer for line

Be

sure

to use correct line

as

but

those

the

01255-1

3-3

Section Paragraphs

III

3-8

to

3-15

Table

3-1.

Methods

of

Triggering

Model 185B

r

3

r

Waveform

Types

Trigger Freq

Over 10

Below

Below 10

10

kc

Possible

Trigger Ckt

Measurement?

to

under

no

Ext

Trig

Gen

4vailable

no

---

Delay

iequired

‘

(no,

test

delay

120 ns)

Line

no

Yes

no

yes

if

ckt

>

1

Xefer

Figure

3-

3

3-4

3-5

3-6

to

3-8.

THE

PRINCIPLE

OSCILLOSCOPE.

3-9.

The action of the sampling oscilloscope issim-

llar

to a strobe light that nization with a turning device, resulting in an apparent slow motion--or the effect of taking moving pictures of a rapidly spinning wheel where shutter speed rotation of the wheel, causing the wheel to appear be turning very slowly, or even turning backwards.

3-10. The sampling of the oscilloscope same way. The sampler plug-in in this case would represent the camera shutter and lens. The sampling circuit input voltage occurs over and over again, sample taken on a succeeding repetition of input sig-

nal

reference point on input signal. 3-11. THE VIEWING ‘WINDOW”. There

maximum and minimum time during which sampling oscilloscope may complete each observation. In the Model 185B, maximum time imum time approximately

is

and at a slightly later time with respect to same

is

nearly

is

accomplished in almost exactly the

opened for very short periods of time and

at

that

time

OF

THE

SAMPLING

is

slightly out of synchro-

the

same as the time for one

signal

is

carefully measured. This

is

0.3

with the sampling

with

each succeeding

is

acertain

100 pseconds and min-

nanoseconds. This time

camera

to

is

referred

120 nanoseconds for the “window” to open after trig-

ger

is

100

pseconds will require special triggering tech-

niques when 3-12. In

cuits must be delayed, or used to permit viewing leading edge of this signal. The following paragraphs will describe different methods available for solving some synchronization problems you may encounter in sampling oscilloscope technique.

3-13.

3-14. GENERAL. 3-15.

be

synchronized with a signal signal received by vertical amplifiers. Furthermore, the system must because sampled signal never actually enters oscilloscope circuits, and therefore ternally for synchronization (in the case 187B, signal figures 3-3

and

measurement situations, and give recommended

instrument arrangement.

to

as

theviewing“window”. Since

received, signals with a period greater than

it

is

necessary to view rise time.

this

case, either

TRIGGERING THE MODEL

As

in any oscilloscope, the

be

is

sampled at probes). Table 3-1 and

to

3-6

list

the

signal

to

an

advanced trigger must

185B.

Model

that

is

time-related to

externally synchronized.

is

not available in-

common types of waveforms

it

sampling

type

185B must

This

of

Model

takes

cir-

be

of

is

3-4

01255-1

Model 185B

Section

III

Paragraphs 3-16 to 3-21

3-16. TRIGGER REPETITION RATE. Model 185B accepts triggers

with

repetition

rates

between 50 cps

and 1000 mc. However, an internal hold-off circuit

limits

maximum sampling rate to about 100 kc. STABILITY provides limited control over hold-off circuit to permit adjustment for maximum stability when

the trigger rate exceeds 100 kc. For frequencies above 100 mc,

a

countdown circuit (adjusted with HIGH

FREQ. STABILITY) reduces frequency of trigger sig-

nal to approximately 10 mc

cuits

will

be

triggered reliably.

so

that synchronizing cir-

3-17. TRIGGERING METHODS.

is

3-18. When limited time-scale speed

lem, and

of synchronizing Model 185B

in a train, and the screen. For

signal frequency must

than one pulse

jitter

is

not excessive, the simplest method

is

to

trigger on one pulse

to

view several succeeding pulses on

this

to

be

will

occur in the 100 Fsec viewing

possible, however, the

at

least

10

notaprob-

kc

so

that

more

“window” of oscilloscope. The following paragraphs

describe a few conditions that dictate

the

method

of

synchronization, and therefore the instrument setup

that

shculd

MODEL

be used.

1856

MODEL

A

IIOOA DELAY LINE

I1

L

1858

SYNC

185A-76A

DELAYED TRIGGER

TAKE-OFF

CIRCUIT

UNDER

TEST

J

LD-S-

574

Figure 3-4. Viewing Signals Below 10 kc by Using

Delayed Trigger to Drive Circuit under Test

to

fall

within 100 Fsec window.

In

order

to

see

the

leading edge, then, you must trigger oscilloscope

just ahead of an input pulse to allow the leading edge

to

fall within time window.

CIRCUIT

QQQ

185

B12IA SYNC PROBE

UNDER

TEST

L

LO-S-576

Figure 3-3. Viewing Signals Above 10 kc

3-19. SIGNAL REPETITION RATES ABOVE 10

Synchronizing on signals above 10

kc

presents few

problems since one or more pulses of a train may

KC.

be

viewed in oscilloscope “window”. The recommended instrument setup for viewing signals above 10 kc shown in figure 3-3, while operating procedures described in figures 3-7 to 3-9. Remember signals above 100 mc, TRIGGERING must

HIGH

FREQ., and STABILITY adjusted withbothHIGH

be

that

set

is

are

for

to

FREQUENCY STABILITY and STABILITY controls.

Note

If

it

is

necessary to examine very fast time (e.g., 10 ns) signals between 10 approximately 100 kc,

it

will not

be

rise

kc

and

possible

using the above method, to magnify presen-

tation sufficiently to examine rise time. It

will

be

necessary in this

case

to resort to

one of the trigger methods given for signals

below 10 kc.

kc

LD

by

-8-173

LD-S-515

Using

SYNC PULSES

Figure

3-

on signals under

will

1100A-76A SYNC TAKE-OFF

DELAY LINE

3-5. Viewing Signals Below

SYNC PULSE OUT

to

Drive Circuit under Test

10

21. Several methods are available for synchronizing

10

kc. Generally the method used

depend on characteristics of circuit under

MODEL

11OOA DELAY LINE

LOAD

1858

test

3-20. SIGNAL REPETITION RATES BELOW

When signal repetition rate

is

below 10 kc,

10

signal

KC.

does not occur frequently enough to allow a full cycle 01255-1

Figure 3-6. Viewing Signals Below 10 kc

when the Circuit under Test Cannot

be

Driven by Synchronizing Pulses

3-5

Section Paragraphs 3-22

III

to

3-38

Model 185B

and the associated equipment available. Table and figures 3-4 to 3-6 give three additional basic instrument setups. Each of them below:

3-22. METHOD ONE (figure 3-4). It trigger Model 185B from a separate source and then delay this same signal to trigger the circuit under measurement

120 ns

An important consideration in this method

is

often possible to tolerate some deterioration of the driving pulses by the delay line or delay circuit, since these pulses serve only to trigger the measured circuit. with sufficiently fast rise time triggering, there

presented to oscilloscope.

3-23. METHOD TWO (figure 3-5). You may use the signal from SYNC PULSE OUTPUT connector to trigger circuit under test. This signal

that

is

scope sweep. See figure 3-12 for basic operating

procedures, If you cannot drive

frequency (100 kc), you can use a repetition rate generator such as

to trigger Model 185B at any rate between 50 cps and

100 kc to produce sync pulses. The sync pulse from

Model 185B when connected to a 50-ohm load.

3-24. METHOD THREE. There are times when the circuit under 10 kc and cannot be driven by any type of sync pulses. This

is

erator must be used for instrument setups and figure 3-10 for operating instructions.

is

(if

inherent delay of measured circuit

or

more, external delay will not

As

long as drive pulses arrive at the circuit

is

no loss of information on signals

suitably delayed from triggering of oscillo-

@

Model

211A

is

normally a +1.5 volt (minimum) pulse

test

operates at repetition rates under

typically the case when a mercury pulse gen-

used. In

this

to

trigger oscilloscope.

case, the signal to be viewed

is

described briefly

is

possible

be

to

provide reliable

is

a

fast

test

circuit at trigger

Square Wave Generator

See figure 3-6

3-1

to

is

required).

is

that

rise

pulse

it

signal fm and jitter become more severe as trigger repetition rate increases. maximum fm trigger signal without affecting the display can expressed as:

where

The formula indicates mc trigger, 0.05% fm for a 100-mc trigger.

3-29. For trigger repetition

there

are

situation should be reliable with up to mc region and correspondingly frequencies.

3-30.

3-31. OBSERVATION

3-32. Due Model 185B screen represents true instantaneous nal amplitude, useful information may from signals

3-33. For instance, occasionally missing, normally on the crt except that appear long the base line. The density of dots in pulse relative to that in the approximate percent

If

self

base

50% of the time, pulse and base line

same.

PULSE ANALYSIS.

the pulse

will

line will be continuous. If the pulse

or

jitter

Maximum fm

f

=

trigger repetition rate in mc

two

count-down circuits in series, and the

is

more complex. However, triggering

to

the

fact

that

are not 100% periodic.

if

of

is

missing most of the time, the pulse

be

represented

As

a

general guide, the

which can

a

maximum of 5% fm for

OF

INTERMITTENT PULSES.

that

one pulse in a pulse trainis

that

pulse will

be

present in the

=

5/f

a

rate8

above 100 mc,

0.05%

fm in the 100-200

less

fm at higher

each sample plotted on

be

a

be

series of dots

sig-

obtained

displayed

will

the

base

line

will

indicate the

time

that

the pulse

by

a

series of dots, while

is

will

missing.

is

appear the

the

present

be

1-

it-

3-25. The signal, decreased in amplitude by any attenuation in the resistive sync probe, 185A-76A sync take-off where Half

the

signal

is

used directly to trigger Model 185B, while the other in unit. When using method three, remember that the resultant vertical calibration of SENSITIVITY setting times probe attenuation times

2.

3-26. The Model approximately nals.

If

a

coil of 3/4 inch

mately 105 feet long to provide about 120-ns delay.

3-27.

3-28. When trigger repetition rate each trigger actuates jitter in trigger signal have no effect upon display (provided there

being viewed).

100 kc and 100 mc, the internal hold-off circuit of

Model 185B comes into play, and

3-6

EFFECTS OF

half

llOOA

1

gc, which

still

wider bandwidth

is

no

For

is

delayed and

delay line

is

sufficient for most sig-

is

or

larger Styroflex cable approxi-

FM

AND JITTER.

a

sampling cycle, and fm and

jitter

between trigger andsignal

trigger repetition rates between

is

fed

to

Model

it

is

divided in

fed

to

vertical plug-

will

be the product

has

a

passband of

desired, you can use

is

below 100kc,

effects

half.

of trigger-

3-34. Conventional oscilloscopes indicate missing pulses by allowing brightness of wave compared line indicates relative frequency of occurrences. You can see that presentation in the form of relative num-

ber

of dots

mation of relative brightness of wave and

3-35. EXAMINING PULSE IRREGULARITIES. 3-36. Figures 3-7

you may expand and examine any portion of a pulse. The horizontal

100

by

vertical ITY control on Model 187B, to a point where a signal

that

fill

the entire 10 x 10 cm graticule,

3-37.

3-38. Figures 3-7 through 3-14 give step-by-step operating instructions. Each step the control

keyed by the same number,

is

setting the TIME SCALE MAGNIFIER. The

axis

initially occupied l/6000th of the screen may

OPERATING INSTRUCTIONS.

or

base

line to

actually easier

to

3-9 describe a method

axis

may be expanded

may be expanded, using the SENSITIV-

connector to which the step refers

strike

through. The

to

brightness of

to

interpretthan an

by

is

numbered and

base

by

which

a

factor of

01255-1

base

esti-

line.

is

Model

185B

Section

Figme

111

3-7

P

I'

(Power Switch on)

1.

Set SCANNING

2.

Set MODE full clockwise.

3.

Set INTENSITY as desired.

4.

Adjust position controls to place trace on crt.

01255-1

to

INTERNAL.

Figme

5.

6.

7.

3-7.

Free Running Trace

If

no trace

and readjust position controls

Adjust FOCUS for a well-defined trace.

Trace should appear approximately as illustrated.

is

visible, press BEAM FINDER

as

necessary.

3-7

Section Figure

III

3-8

I

!'

I

!

I

1

Q

P

Model

185B

..

I

!

i

L

Follow

1.

Connect trigger signal to trigger INPUT.

2.

Set

3.

Set

4.

Connect probe to signal to If delay

to figure

instructions in figure

TIME SCALE MAGNIFIER

TRIGGER SLOPE as appropriate.

is

required (paragraph 3-17), refer

3-10.

3-7.

to

be

viewed. Note:

XI.

6.

Set

MODE

while maintaining reliable triggering.

7.

Adjust

amplitude.

8.

Set TIME SCALE as desired CAL for calibrated time scale).

9.

Set

DENSITY as

while maintaining minimum flicker.

as

far

counterclockwise as possible

SENSITIVITY for the desired

far

clockwise

(set

VERNIER to

as

signal

possible

5.

Set TRIGGERING trigger frequency and amplitude. presentation.

3-8

as

required, depending on

Figure

3-8.

1O.H

Unmagnified Trace

necessary, adjust STABILITY for

stable

01255-1

Model

185B

P

Section

Figure

III

3-9

Follow instructions in figures

1.

Turn TIME SCALE MAGNIFIER clockwise

about four ranges (depending on amount of

magnification desired).

2.

Rotate TIME SCALE MAGNIFIER andDELAY clockwise until the desired portion of the trace

01255-1

3-7

and

Figure

3-8.

Magnified Trace

becomes visible. Adjust DELAY

to center the display.

3.

Adjust SENSITIVITY and VERTICAL POSITION

to

amplify and center trace.

4.

Finally, adjust TIME SCALE MAGNIFIERand

DELAY

to

achieve desired magnification.

if

necessary,

3-9

Section Figure

III

3-10

Model

I

l85B

P

Follow instructions in figure

Connect

tem as illustrated above. Note: Be sure

nated to prevent reflection which would result in misleading indications.

2.

Connect resistive divider probe to signal to

be

viewed.

3-10

185B

that

to

system

3-7. 3.

'looA

is

Line

SYs-

properly termi-

Figure

3-10.

Set

TRIGGERING

trigger frequency and amplitude.

4.

Set MODE as far counterclockwise while maintaining reliable triggering.

5.

Adjust SENSITIVITY as required. Note: Remember that signal factor

of

1/2.

6.

Set

TIME SCALE as required.

7.

Set STABILITY for stable presentation.

Viewing Delayed Signal

as

required depending on

as

will

be

attenuated by a

possible

01255-1

I

Model 185B

Section

Figure 3-11

111

____1i

'I I

Follow instructions in figure 3-7.

1.

Connect tem

2. Connect input of sync take-off

3. Connect output of Model to be triaaered. Note: If more

be

Model

as

illustrated above.

th&

needed.

120 ns delay, the delay line

185B to

llOOA

test

Delay Line sys-

to

trigger source.

to

test circuit

circuit

itself

will

has

not

Connect probe to signal to Set

5.

6.

,.

8.

TRIGGERING as required depending on

trigger frequency and amplitude. Adjust SENSITIVITY

Set

TIME

SCALE

Adjust STABILITY for

as

be

as

required.

stable

viewed.

presentation.

4.

I

Figure 3-11. Using Delayed Trigger

01255-1 3-11

Section Figure

III

3-12

Model

185B

Follow instructions in figure

If

external triggering

1.

ger

to

INPUT.

2.

Set TRIGGER SLOPE as appropriate.

3.

Set CALIBRATOR counter clockwise.

4.

Obtain delayed sync pulse for triggering ex-

ternal circuit from

this

nect

pulse to trigger circuit under test.

AND

SYNC

3-7.

is

desired connect trig-

SYNC PULSE

PULSE output, Con-

Figure

full

3-12.

5.

6.

7.

8.

Delayed

Connect probe

If

external triggering

ING

as

quency and amplitude.

If

external triggering far counterclockwise taining reliable triggering; otherwise MODE should

Adjust SENSITIVITY for desired amplitude.

Sync

be

Pulse

to

signal to

required depending on trigger fre-

full

clockwise.

be

viewed.

is

used, set TRIGGER-

is

used, set MODE

as

possible while

main-

signal

as

3-12 01255-1

Model

185B

w

Figures

Section

3-13

and

III

3-14

Obtain desired presentation on crt. ures

3-7

to

3-9.

1.

Connect

external

scanning signal to INPUT

See

Figure

fig- EXT SCAN. (Input: 0 volts places scan

left

3-13.

edge of crt;

2.

Set SCANNING

External Scan

(REAR

+12

to

EXTERNAL.

OF

1858

volts at right edge.)

)

at

Obtain desired presentation ures

3-7

to

3-9.

1.

Connect X input SCAN OUTPUT. (Output: 0 volts = left edge crt;

+12

volts = right edge.)

01255-1 3-13

of

X-Y

on

recorder

crt.

See fig-

to

TIME BASE

Figure

3-14.

2.

Connect Y input of recorder

OUTPUT. (Output:

crt;

+1

3.

Set SCANNING

4.

If

it

is

set

of

Recording the Signal

SCANNING

with SCAN.

-1

volt = top edge.)

to

RECORD.

desired

to

scan more slowly

to

MANUAL and scan signal

to

CHAN

A

(or

volt = bottom edge of

or

B)

rapidly,

I

Section

Figure

IV

4-1

Model

185B

1

r

c

'I

.

4-0

01255-1

Model 185B

Section

Paragraphs 4-1 to 4-16

IV

1

SECTION

PRINCIPLES

4-1.

INTRODUCTION.

4-2. GENERAL. The Model 185B oscilloscope and

its

vertical plug-in unit form a samplingunit for mea-

suring

is

graphs the information presented

4-3. This tween the

more detailed circuit description. An understanding of the following information should prove effectively troubleshooting Model 185B.

4-4.

4-5. GENERAL. 4-6. Figure 4-1,

Model 185B, shows functional relationships of each

major

ing the relationship between functional groups, the Model 187B Dual-Channel Vertical Amplifier has

been shown 4-7. INPUT CIRCUITS.

4-8. The input circuits accept the trigger

The controls provide

nals

trigger circuits also select whether triggering will on the positive

4-9. --GATE GENERATOR. 4-10.

ator produces the basic timing pulse for Model 185B time base circuits (ramp generator, comparator and comparator blocking oscillator, and horizontal- scan generator). Usually the ramp-gate generator gized by input trigger signal; however, run for certain applications. Maximum repetition rate for basic timing pulse 200 nsec/cm and faster, but decreases in proportion

-'

to

200 nsec/cm, becoming about 5 kc at 10 lsec/cm.

Thus when trigger repetition rate mum timing pulse rate, one timing pulse for each trigger pulse; when trigger repetition exceeds maximum timing pulse rate, trigger signal

is

(ramp-gate pulse) maintains a strict time relationship

to

input trigger frequency.

4-11. USES

gate pulse

voltage in time-base circuits, 2) back network

is

extender and calibrator

fast repetitive signals. The circuit description

necessarily complex; a thorough reading of para-

3-1

to 3-34 will prove helpful inunderstanding

in

this section.

brief

major

BLOCK DIAGRAM DESCRIPTION.

section.

of various frequencies and amplitudes. The

RAMP

discussion of the relationship

functional groups

a

simplified block diagram of the

For

purposes of clarity inunderstand-

as

a part of figure 4-1.

for

stable triggering from sig-

or

negative slope of the input signal.

GATE PULSE. The ramp-gate gener-

is

followed

an

signal,

is

it

may be

is

100 kc for time

selected time scale for time scales slower than

is

less than

counted down. In

input trigger frequency

OF

has

to

not shown in figure 4-1), 3)

circuits,

sidls.

all

cases, basic timing pulse

or

to

some submultiple of

RAMP-GATE PULSE. The ramp-

four

functions:

complete

4)

it

its

own

it

triggers

initiates

1)

it

initiates a ramp

it

is

used in a feed-

cycle (this feedback

the

delayed sync pulse

scales

is

generated

ramp-gate

be-

by

aid in

be

ener-

free

maxi-

rate

OF

a

IV

OPERATION

4-12. RAMP-GATE EXTENDER AND GENERATOR CIRCUIT. The ramp-gate extender circuit increases the duration of ramp-gate pulse, producing an tended pulse whose duration tween input trigger, ti, and moment just after sampling,

h.

control of ramp-gate extender circuit (for TIME SCALE settings slower than 100 nsec/cm), the ramp generator produces a linearly-rising voltage whose

slope

This ramp voltage 4-13. TIME-BASE CIRCUITS.

4-14. COMPARATOR. In the comparator circuit, the

ramp voltage

(a

horizontal-scan generator when SCANNING TERNAL). When ramp voltage reaches coincidence with horizontal-scan voltage at time t3, the comparator produces a pulse which triggers the comparator blocking oscillator.

4-15. COMPARATOR BLOCKING OSCILLATOR. time t3, the comparator blocking oscillator produces four pulses: two (the sampler trigger and stretcher trigger) initiate sampling action of plug-in, the third

is

used in horizontal-scan (staircase) generator, and the fourth voltage.

4-16. HORIZONTAL-SCAN GENERATOR. The output of the horizontal-scan generator the horizontal amplifier and, through TIME SCALE MAGNIFIER switch, to the comparator. The mode horizontal operation SCANNING switch S203. There operation:

a. INTERNAL: the scan voltage staircase-voltage generator. The beam across crt and appears as a series

b.

tioning potentiometer R255A (figure 5-17) which brought out to front panel as SCAN control. The display appears as a spot which can be horizontally positioned at

c. RECORD: the scan voltage charging voltage across capacitor C240. The beam

is

output may be taken from OUTPUT TIME BASE SCAN connector 5202, and vertical output from OUTPUT CHANNEL Aconnector

B connector 53.)

d. RESET OR EXTERNAL: the scan voltage rived from

PUT EXT SCAN connector 5201. The RESET OR EXTERNAL position also Model 185B

Triggered by the ramp-gate pulse andunder

is

dependent on setting of TIME SCALE switch.

is

fed to the comparator.

is

step level

MANUAL: the scan voltage

swept slowly across face of

compared

in

staircase voltage generated by the

is

used

to

initiate the termination of ramp

is

will

by means of the SCAN control.

an

external source, applied through

is

used on RECORD.

is

dependent on time

to

horizontal-scan voltage

is

applied

determined by the setting of

are

four modes of

is

derived from

of

discrete points.

is

derived

is

derived from

tube.

(The horizontal

52

or

OUTPUT CHANNEL

is

used

to

reset trace when

is

at IN-

to

by

ex-

be-

At

both

swept

posi-

is

de-

IN-

of

is

01255-1

4-1

Section IV

Paragraphs 4-17

to

Model 185B

4-28

rl

n

f3

Figure 4-2. Time-Base Determination

4-17. CALIBRATOR.

is

4-18. The calibrator

a.

A

pulse amplifier and pulse extender-shaper:

a

pulse from the ramp-gate blocking oscillator amplified, extended, and shaped which connector. There between signal applied to front panel TRIGGERING INPUT and signal available at SYNC PULSE OUTPUT.

gered sine wave for the duration of sync pulse.

ages from depending on setting of CALIBRATOR AND SYNC PULSE switch.

4-19. VERTICAL AMPLIFIER AND ELECTRONIC

4-20. The vertical amplifier amplifies

vertical plug-in unit, and applies amplified signal vertical deflection plates of cathode-ray tube (crt).

The electronic switch provides switching action necessary for dual-trace operation of plug-in unit.

4-21. HOFUZONTAL AMPLIFIER. 4-22. The horizontal amplifier amplifies the partic-

ular horizontal drive signal setting of SCANNING switch and applies

zontal deflection plates of the crt.

4-23.

4-24. actual speed of the horizontal beam across the face of base in sec/cm. The time base of Model 185Bis dependent entirely upon time advance, between successive samples, deflection voltage

ods

slope of ramp signal (TIME SCALE control), and by varying amplitude of horizontal-scan voltage to comparator in relation to horizontal-scan voltage to

is

made available at SYNC PULSE OUTPUT

is

b.

A

pulsed 50-mc oscillator:

by

amplified ramp-gate pulse,

c.

A

dc voltage divider:

0

volts dc

SWITCH.

TIME-BASE DETERMINATION.

At

this point,

the

cathode-ray tube has no relation

as

to

are used

to

vary

made up of three circuits:

to

a fast-rise pulse

approximately a 120-nsec delay

this

circuit, trig-

puts

this

circuit provides volt-

to

1000 millivolts dc, the level

that

has been selected by

it

should be emphasized .that the

compared

the crt.

this

time advance:

to

some horizontal

In

Model 185Btwo meth-

1)

RAMP GATE PULSE

STAIRCASE VOLTAGE

(HEAVY

RAMP VOLTAGE

(LIGHT. LINE)

SIGNAL ON

CATHODE RAY TUBE

(DOTTED LINE)

TRIGGER AND

SAMPLED SIGNAL

(SOLID LINE)

out a 50-mc

signal

from

it

to hori-

to

the time

by varying

is

to

2)

4

n

n n

LINE)

horizontal amplifier

ting of TIME SCALE MAGNIFIER control). 4-25. Figure 4-2 shows

SCALE control (varying slope of ramp signal). Note

that

as slope decreases, more time elapses between

ramp-gate pulse,

dence between ramp and horizontal-scan voltage, t3

(t3

=

time at which input signal

sult

is

that

a greater part of

ered

between successive samples, giving more cycles per centimeter of Model 185B will be discussed in more detail.

4-26.

4-27. GENERAL. Before detailed explanation of circuit operation of the operation of tunnel diodes in Model 185B triggering and time-base circuits. Tunnel diodes in triggering and time-base circuits have

modes of operation: the diode oscillates sociated circuitry, and

is

gered back 4-28. ASTABLE OPERATION. Figure 4-3A shows a

typical circuit consisting of a low-voltage source which supplies bias current to the tunnel diode through an inductor which acts as during switching times.

junction capacity and stray capacity are indicated as a capacitor across the diode (the total of will ing discussion). The diode the E-I curve in figure 4-3A.

flows through the inductor and diode, in diode voltage will rise from the origin toward point C,

its

on the knee of the E-I curve, negative resistance region and diode current begins to decrease. However, the energy stored in the inductor’s magnetic field prevents

TUNNEL

triggered into one state where

to

the

a. The external load

be

termed diode junction capacity in

b. When power

operating point.

(this

ratio

the

tl

and the time of voltage coinci-

to

the viewer. After basic operation

is

discussed, time-base determination

DIODE

is

attempted, there will be adiscussion

at

original

OPERATION.

1)

free running (astable), where

a frequency determined by

2)

bistable, where the diode

state.

a

is

applied to the circuit, current

As

diode

n

n n

.-L

is

determined

effect

constant current source

shown as R1; the diode

is

of varying TIME

is

sampled). The

the

input signal

it

stays until trig-

biased

by

two

this

capacity

the

at

point C on

is

basic

follow-

series,

voltages passes point B

the

diode enters

its

current from

I”

set-

re-

cov-

the

as-

.

and

its

4- 2

01255-1

Model 185B Section IV

=

+0.2v

-12.6V

Paragraphs 4-29

to

4-35

TUNNEL

DIODE

CRI

fb,

-

A. ASTABLE

Figure 4-3. Tunnel-Diode Operation

so

decreasing,

current and inductor current flows into diode junction

capacity. Since diode junction capacitance this difference current causes a sharp voltage across the junction capacity and hence across the diode. This voltage

E-I curve. equals the current supplied from

source, and

the voltage across the diode exceeds the supply voltage. Since current through the inductor only during switching, current diode voltage When diode voltage reaches point E, tunnel diode CR1 again enters current pacity now begins over again.

time (time BD) pacitance and peak current. Pulse width (time DE) and hold-off time (time AB) are determined inductor, diode resistance, and power source resistance. Assuming the inductor acts as a constant current source for load resistance determines the slope of lines BD and EA.

4-29. BISTABLE OPERATION. Figure 4-3B shows

a bistable circuit of the type used inModel 185B triggering circuit. In this case there

with

CR1 stable at emitter of Q1 (or a negative pulse to the current through Q1, and hence the tunnel diode current, will increase, current knee of the curve, the tunnel diode enters

negative resistance region. Diode current therefore begins

stant current source, however, and prevents current

from decreasing; the current difference flows into the

rapidly to point

again to zero, diode voltage falls to

mains until

to

is

c. For

tunnel diode CR1 as part of

is

biased at point R on

to

junction capacity.

drop below Iv.

the current difference between diode

is

rises

rapidly to point D on

At

point

D,

diode conduction current

the

constant-current

so

the voltage stops rising.

starts

its

again held constant, and diode junction

forced to discharge to point

a

large value of load resistance, pulse

to fall toward operating point C.

negative resistance region. Inductor

is

determined by diode junction ca-

the

times involved, the size

is

the

this

point.

If

a positive pulse

At

this

is

to decrease, and

A.

a

PNP

its

E-I curve, and

constant

The process

transistor

collector load.

is

fed

base),

As

the current passes the high

decrease. Transistor Q1 acts as

As

a

result, diode voltage

V,

then when the input pulse falls

a

negative reset pulse causes the current

U

the

where

small,

rise

the

time

ca-

rise

by

the

of

the

to

the the

con-

rises

it

re-

is

its

CRI

TUNNEL

DIODE

LD-L-545

E. BISTABLE

4-30. The circuit described in paragraph 4-29 can

be

made monostable by increasing transistor current

to

a point where a current greater than CR1

is

stable at point W on the curve shown

4-3B. Momentarily reducing tunnel diode current

to

less than that shown at point T in figure 4-3B will cause the tunnel diode to go through a cycle from T

to R to

W

4-31.

4-32. GENERAL. 4-33. The following discussion

the synchronizing circuits in Model 185B. otherwise noted, all reference to “signal” in the following circuit explanation will refer to the triggering

pulse under discussion rather than the signal to

viewed. the crt refers zontal amplifier. Refer figure 5-13 and figure 4-4 in the followingdiscussion.

4-34. TRIGGER INPUT. 4-35. The trigger signal

ING INPUT connector 5101. TRIGGERING

SlOl

on

(less

TRIGGERING the input trigger gate generator.

greater than 150 mv and frequency below 100 mc.

this

through

before being passed to the ramp-gate generator.

In

to a count-down circuit before being passed to rampgate generator. lator consisting of diode CR120, inductor L101, and low-impedance bias voltage source R155, R156 (fig-

ure 4-5A)

S

to

until triggered by another pulse.

TRIGGERING

All

is

adjusted to one of three positions, depending

frequency and amplitude of input trigger.

a.

SENSITIVE: for small amplitude trigger

than 150 mv) below 100 mc. In this position of

b. NORMAL: for trigger signals of amplitude

position of TRIGGERING the input trigger passes

a

20-db attenuator consisting of R158, R159

c.

HIGH FREQ: for trigger signals above 100 mc.

this position

is

the

tunnel diode

its

peak current. In this case,

V

to

W.

The circuit

CIRCUITS.

reference

to

horizontal-scan voltage

the voltage at the input to the hori-

to

is

always receiving

in

figure

will

remain at point

deals

primarily with

Unless

the schematic diagram,

connected

to

TRIGGER-

switch

signals

is

passed

of

TRIGGEFUNG, trigger

A

free-running tunnel diode oscil-

used to count down the input frequency

to

the ramp

is

applied

be

to

In

01255-1

4-

3

Section IV Paragraphs 4-36 to 4-38

to

approximately 10 mc. The trigger signal passes through a trigger gate consisting of diode CR121, CR122, and associated bias circuits. With no input trigger, both CR121 and CR122 are conducting. The current through CR121 passes through R152 from the

+12.6 volt source, while the current through CR122 passes through tunnel diode CR120. CR120 (with

L101) oscillates at a frequency around 10 mc with no

input trigger. (The basic operation of

this

circuit

is

explained in paragraph 4-26.) When an input signal

is

applied, CR121 and CR122 clip this signal. During the positive clipping action, tunnel diode CR120 ceives pulses

CR122), and rent knee occurs, CR120

of

current (since

if

CR120

(see

figure 4-5B) when one of these pulses

will

is

near the top of

change

it

states.

is

in series with

its

Inductor L101,

re-

high cur-

HIGH FREQUENCY STABILITY, adjusts frequency of CR120-Ll01 oscillator relative

so

that

an

input pulse

time relationship to

sists

of count-down circuit output pulses with a

will

always maintain the same

the

oscillator. The result con-

to

input frequency

fre-

quency near 10 mc, but synchronized with input signal. 4-36. RAMP-GATE GENERATOR CIRCUITS. 4-37. PULSE GENERATOR. The output of trigger

mode selected

is

fed to TRIGGER SLOPE switch S102

Model 185B

through transformer T101. S102 determines polarity of signal

lecting triggering on either positive or negative

to

pulse generator Q104-Ql05-CR116,

se-

slope.

Transistors Q104 and Q105 are connected as adifferentia1 amplifier which triggers tunnel diode CR116. This circuit constitutes a pulse generator whose

quency

is

determined

by

input pulses and/or hold-off

fre-

multivibrator V101B/V102AB (described in paragraph 4-41). The pulse generator circuit operating

states

as

set

by

MODE control: GER, a state where circuit must input circuit

in

order to generate pulses,

has

two

1)

be

triggered from

basic

TRIG-

and

2)

FREE RUN, where circuit generates :pulses whose

frequency

is

determined by hold-off multivibrator V101B/V102AB (figure 4-4). Resistor R160, MODE control, and R157, Free Run Adjust, determine basic operating state by adjusting current through Q104 which furnishes tunnel

diode

bias current;

this

is

equivalent to adjusting point R, figure 4-3B. 4-38. The circuit operates

MODE trigger signal switch S102

is

set

so

that

circuit must be triggered): Input

is

applied to Tl01.

is

in the + position, signal will be fed through TlOl primary (since TI01 secondary shorted, primary presents a very low impedance signal)

to

base of Q105. IfSlO2isset in the - position,

as

follows (assuming

If

TRIGGER SLOPE

is

to

d

4-4

+

12.6V

Figure 4-4. Triggering-Circuit Block Diagram

ID.L.8U

01255-1

Model 185B

A*.

:

C135 CR121

TRIGGER

SIGNAL

IN

R152

i

CR122

'io

TRIGGER OUT

CR120 TUNNEL DIODE

I

1

THIS

I

CR120

I

STATE

PULSE

CAUSES

TO CHANGE

Paragraphs 4-39 to 4-44

Section

IV

TRIGGER SIGNAL

-

~~~

Figure

operation depends on frequency of trigger signal. For high frequencies,

base

of

effective and signal case, base of Q105 actuate triggering circuits.

4-39.

Q105,

sulting positive pulse emitter coupling capacitor, C145. The increased positive voltage at emitter of Q104 increases conduction in (figure 4-3B), tunnel diode CR116 switches

voltage stable

remains

vibrator (paragraph 4-41). (Any further trigger pulses

occurring before reset The entiated

4106, and fed to ramp-gate blocking oscillator Q107 through CR131. CR131 Q107

Q105. For low frequencies TlOl becomes

this

circuit must have either a positive pulse

If

a

positive pulse

its

emitter becomes more positive. The

that

element. When 4104 current increases

until

result

is

by

to

negative pulses.

signal

or

a negative pulse

state

reset

a

positive voltage step which

C146 and R178, amplified and inverted

is

coupled through TlOl

is

applied to base of Q104.

is

applied to the

is

coupled

(see

paragraph 4-29), where

by

a pulse from hold-off multi-

will

have no effect on CR116.)

limits

signal at the base of

4-5. Tunnel-Diode Count-Down Circuit

to

in-

In

any

to

base of Q104

base

to

of

re-

to

Q104 via common

to

IP

to

its

high-

it

is

differ-

by

VOLTAGE INCREASING

4-4L HOLD-OFF MULTIVIBRATOR. The ramp-

gate pulse coupled by T103

and R186, then delayed

is

then fed through CR107 where the negative spike

is

clipped off and the positive spike hold-off multivibrator (V101B/V102AB). With a positive spike on VlOlB. Hold-off multivibrator V101B/V102B remains in and

all

circuits have had time to recover. The exact hold-off time switch S202 and

4-42. When V101B/V102B switch mer

states

resulting negative voltage, coupled by capacitor C115, back-biases diode CR124 and forward-biases CR125.

In

this

condition of the circuit, capacitor C115 now

effectively in parallel

current from the diode. Current through the diode drops below I, (figure 4-3B) momentarily, returning CR116 to mains until another input trigger

its

this

state

is

determined by settingof

(VlOlB conducting, V102B cut

its

low-voltage stable point where

1

grid, V102B conducts, cutting off

until

after

by

setting of STABILITY control.

with

-

0.

is

differentiated by C155

psec by DL101. The pulse

is

sample has been taken

back

tunnel diode CR116, diverts

is

received.

W-

I-

305

applied to

TIME

to their for-

SCALE

off),

it

the

re-

4-40. RAMP-GATE BLOCKING OSCILLATOR. Transistor 4107 produces pulse of about 1.5 psec duration. This gate pulse and

a. To supply a gating

b.

To supply trigger

circuit.

c.

To provide trigger

d. To generate in pulse generator pletes cycle

In

order

ation of the reset pulse

01255-1

it

has

by

which ramp-gate pulse

to

simplify the following discussion, gener-

a

typical blocking-oscillator

four functions:

signal

a reset

pulse for tunneldiode CR116

circuit.

is

the ramp-

to ramp-gate diode.

to

ramp-gate extender

to

calibrator.

This reset pulse com-

is

produced.

will

be discussed

first.

4-43. There

reset

turned on. Also, under large signal conditions the

reset

pulse may these reasons, an auxiliary reset oscillator sures resetting of CR116 to the low-voltage included in the triggering circuit.

4-44. Basically,

cuit consists of a voltage-sensitive switch (four-layer

diode CR111) with a small load, R135, that tively coupled by C126 across the diode. Resistor R134 and the -100 volt supply constitute

source for the circuit.

to

is

a possibility that CR116 may not be

the

low-voltage state when Model 185B

be

overcome

the

auxiliary

by

a

large trigger. For

reset

oscillator

that

state

is

capaci-

a

current

is

as-

is

cir-

4-5

Section Paragraphs 4-45

IV

t

IOOV

to

4-51

WQIO3

t

IOOV

Model 185B

Wo103

TI03

@

(iiJ

CR136

-

03

-

CURRENT DURING WAITING PERIOD

-

Jl!

+

..

IOOV

A

CR137

CR201

R210

Figure

CR207

0205

R212

-

---

CURRENT CURRENT DURING EXTENDED RAMP

4-6. Ramp Generator

DURING

RAMP

e

GATE

A

+TO

!IL

CR207

8

0205

OF

so-

S202

I-

we

.

4-45. When Model 185B through R134. When voltage across C126, and therefore across the diode, reaches about 20 volts, CRlll conducts and quickly discharges C126. The circuit

delivers

a

second which

brator V101B/V102AB.

4-46. RAMP-GATE EXTENDER AND GENERATOR

4-47. The ramp-gate pulse

the

is

various dc currents circuit.

4-48. Figure 4-6 shows dc current paths during phases of period (after end of last sample and before occurrence of next trigger), current (figure 4-6A) flows from

+lo0 volt and +250 volt sources into both delay

erence-voltage source (Q2Ol-0202) and -100 volt supply. Since diodes CR136 and CR201 ing, points tial The voltage (point C) at which ramp

low-impedance reference-voltage source Q201-Q202, and DELAY control R212 Adjusting DELAY control R212 therefore sets voltage at points

a

20-volt pulse

is

CIRCUITS.

ramp-gate extender circuit, Before

discussed, however, we should understand

Model

(disregarding forward potential of

A,

185B operation. During the waiting

A,

B, C, and D are all at

B,

C, and D.

is

turned on, C126 charges

2

p

seconds wide about once

used to trigger hold-off multivi-

is

also used

to

this

trigger

circuit

the

that

flow in the T103 secondary

all

ref-

are

conduct-

the

same poten-

the

diodes).

is

set by

on Q201-Q202.

adjusts

How

starts

bias

this

voltage affects

the

operation of ramp-gate extender and ramp-volt-

age

generator circuits

4-49. Transistors QlOl and Ql02 constitute rampgate extender multivibrator. This circuit stable multivibrator with 500 ms; however, in actual operation determined by length of time between input trigger and moment of sampling.

4-50. When ramp-gate pulse occurs, negative-going pulse from pin 7 of T103 causes Ql02

to

go to cutoff, forcing Q101 into conduction. When Q102 cuts increasing conduction Q103, and therefore the anode of diode CR137 become more positive,

4-51. gate pulse step b) (figure 4-6B) anode of CR137 now tential.) Diode CR201, suddenly back-biased, cuts off, depriving point C of

this

source for a capacitor in the TIME SCALE switch. The result switch begins to charge up toward +250 volts through

R210 and R211, and the level

This

off,

its

At

the same time,

at

pin 6 of T103

causes

to

happens, +250 volts and R210 form a current

is

that

rising

voltage

is

discussed below.

is

a

mono-

a

period of approximately

its

period

the

resulting

collector becomes more positive,

in

Q103, causing emitter of

the

positive-going ramp

(see

paragraph4-40,

the

voltage at A and therefore

become positive. (The cathode and

are

at very nearly the samepo-

its

path

to

-100 volts. When

the capacitor

is

the ramp signal.

at

point C

in

the TIME SCALE

starts

to

at

rise.

is

to

B

4-6

01255-1

Model 185B

Paragraphs 4-52 to 4-64

Section

IV

Note

The ramp signal the outset due to the initial drop acrossR211

(see waveform ing voltage of the ramp signal depends onthe output of delay reference-voltage generator Q201-Q202.

4-52. Meanwhile, the 1.5psec ramp-gate pulse

to

gins

continue

has the

100 psec/cm the ramp-gate pulse must be extended.

The circuit accomplishes

When

value than the anode of CR137, CR137 begins conduction, and the Q103 emitter voltage

B*

changes

a

on CR201* (The ramp-gate extender multivibrator does not change state until, pling, the ramp oscillator Q208-T203 reaches the base of transistor

QlOL

causes transistor conduction, which changes conduction through Q103.)

4-53. When

changes

sends a pulse to trigger

The reset blocking oscillator then

the

negative, back-biasing CR137. The junction of CR201 and R195, deprived now of positive voltage through

CR137. returns of DELAY, and conduction begins again through CR201.

The circuit

remains

from the ramp-gate blocking oscillator.

4-54.

4-55. Up

cuit

a

linearly rising ramp front panel. We will now discuss

and how age to produce a gating (sampler) trigger for the vertical Plug-in unit. Refer

(schematic diagram) in the following discussion.

4-56. COMPARATOR.

4-57. THE RAMP. To understand the method

achieving changes in time understand the ramp and

and horizontal-scan circuits.

ramp voltage reaching coincidence

tal-scan voltage at time t3.

4-58. Referring

the ramp

decay. The ramp voltage at C, however, must

to

rise

been

longest

time

ramp-gate

However,

state,

heavily-conducting Q103

positive

bias

at

reset

The trailing edge of the ramp reset pulse

the

state

it

does

capacitor

ramp*

TIME-BASE

that

circuit

be

varied

in

2,

It

is

now at

triggered again

to

this

resets itself (the ramp-gate pulse generator),

for

e*ending

it

is

compared with the horizontal-scan volt-

tl,

then any voltage along the ramp can

makes

at

C,

Since

ramp-gate

the

at

an initial jump

figure 4-6B). The

asampleofthe

ramp

must

be

for

time

this

“extension”

A

drops

to

a

more

is

extender

coupled to point

start-

input

as

longer

as

follows:

negative

at

signal

long

maintain

point

B,

maintaining

after

the moment of sam-

pulse from comparator blocking

Qlol

to cut off, biasing Q102 into

ramp-gate exhder multivibrator

two

things

reset

TIME

simultaneously:

blocking oscillator Q203.

SCALE

emitter

to

a level determined by the setting

its

“waiting period”, where

the

CIRCUITS.

point we have discussed a pulse

this

whose starting

a

to

figure 4-7 and figure 5-17

base,

its

relation to the comparator

Figure

to

figure 4-8,

if

the

back

fires,

discharging

switch,

Of

we call the

terminating

‘lo3

to

ramp-gate pulse

and

(DELAY)

this

ramp voltage

it

is

essential

4-8 shows the

with

a

dc horizon-

more

“‘tage

On

start

be-

as

than

bias

1)

cir-

the

be

It

it

of

to

of

assigned a time value, depending on how long the ramp

can corresponds

4-59. Now

requires some kind of voltage-sensitive device. The comparator

to

the desired point in time comparator, and when the ramp reaches that voltage (coincidence), the comparator

signal triggers the sequence which causes a sample

of the input signal voltage which corresponds

is

the horizontal-scan voltage.

4-60.

is

steepened (dotted line) coincidence occurs sooner;

that

ramp The cumulative effect of steepening the ramp

in

figure 4-2. The relationship of fie horizontal scan

to

the circuit and the ramp

more thoroughly in paragraph 4-66. 4-61.

a

diiferential

with

of

~205 exceeds the base voltage of Q206, which

the condition under which coincidence occurs, the

fast

goes

is

dependent Q205 exceeds the base voltage of Q206; inother words,

the

circuit

4-62. The particular horizontal-scan voltage being

used,

voltage

This Q206 base voltage. then horizontal position of-&e spot

poses of this explanation, assume the spot

extreme left of the 4-63. The horizontal-scan voltage for the comparator

a

is

brought through an attenuator, TIME SCALE MAGNIFIER switch S201.

clockwise and TIME SCALE MAGNIFIER set to (the no attenuation setting), the voltage at the base of

Q206

therefore the emitter of Q205)

tive.

the base of 8205 by delay reference-voltage generator Q201, Q202, and CR207. Negligible current flows through Q205 at

this

diode CR209. 4-64. When the ramp-gate pulse occurs, the ramp

takes

Q205

the ramp voltage on the

until the Q205 base voltage exceeds the base voltage

of Q206, and Q205 conducts. Conduction of Q205

to

reach that voltage. From

see

that

any voltage along a ramp of given slope

to

a specific time value.

to

pick

out

a point in time along the ramp

is

just

this.

A

voltage which corresponds

is

fed to one side of the

fires.

to

be

taken. In Model 185B, the

to

the desired pointintime

Note

in

figure

is,

less

time

(trigger

COMPARATOR.

its

rise

negative

resultant

time) and coincidence (sampling time),

amplifier

collector

produces

time.

with

on the length of time the base voltage of

pulse

operates

or

a

voltage

in

use,

is

approximately 0 volts, while

Before generation

time, and no current flows through tunnel

its

initial voltage step, and the voltage on the

base

rises to -0.2 volt.

4-8, that when the ramp slope

elapses

As

Soon

respect

The

duration

lasts

as

follows~

proportional

is

always present on the Q206 base.

between

The

with

a

Any

a

voltage

as

the

to

the

of

until

the

crt

about

With DELAY set

the

tunnel

diode

time

the

step

base

Qzos

the

resultant

ramp

to

the

horizontal-scan

is

proportional to the

on

the

to

start

its

is

slightly more nega-

of

is

the ramp voltage, however,

held at aDDroximately

After

the initial spurt,

base

of Q205 rises linearly

it takes

this,

then we

The resulting

start

of

the

is

shown

is

covered

is

essentially

in

series

base

voltage

is

having a very

of

Q205

again

base,

the

step

pulse

is

reset.

crt. For pur-

full

emitter(and

is

on the

a sweep.

counter-

-0.9

volts

The

X1

01255-1

4-7

Section

Paragraphs 4-85 to 4-87

IV

RAMP RESET TRIGGER PULSE

iy-

RAMP-SATE

EXTENDER

MULTIVIBRATMI

t

250VF

I4

RAMP RESET PULSE

1

FIT

RAMP RESET

r

PULSE

AMPLlf

IER

TRIGGERS

TO

SAMPLING

PLUG-IN

-

f

fm

TUNNEL

DIODE

220K

R255A

I

STAIRCASE

RESET

BLOCK.

OX.

Model 185B

I-

I

I-

I

1-

DELAY REFERENCE SENERATOR

Figure 4-7. Time-Base Block Diagram

marks the time of coincidence. The resulting current through Q205 and CR209 exceeds IP (figure 4-3), CR209 changes age across CR209

4-65.

As

pulse from CR209

reset

ramp Meanwhile the horizontal-scan generator has stepped

the

Q206 base voltage the actual step amplitude depending on the setting of SCAN DENSITY. When the next trigger arrives the ramp again and then the with the process continues until a horizontal sweep completed.

base

that

rises

voltage

state

(paragraph 4-29), and the volt-

rises.

mentioned above (paragraph 4-61),

(the

blocking oscillator Q203 resets the ramp.

takes

linearly (this time alittlefarther) until

of Q206. The comparator

comparator pulse) lasts until

to

a

slightly more positive value,

its

initial voltage step

or

4205 again reaches coincidence

fires

to

-0.2 volt

again, and

this

is

a. The time scale in sec/cm

by

the TIME SCALE switch when no attenuation

RAMP

VOLTAGE

I

tl

5'

TIME

Figure 4-8. Ramp Voltage vs Time

I

t3

-

is

the value selected

G-S-554

I0-L-m

is

I

4-66. TIME SCALE/MAGNIFIER RELATIONSHIP.

4-67. The following discusses why time pendent only on the slope of the ramp (determined by the setting of TIME SCALE) and attenuation of the horizontal-scan voltage (determined by the setting of TIME SCALE MAGNIFIER). There portant p9ints TIME SCALE/TIME SCALE MAGNIFIER relationship:

4-8

to

remember when thinking about the

scale

are

is

de-

two im-

inserted (by TIME SCALE MAGNIFIER and/or VERNIER) between the scan voltage at the input the horizontal amplifier and the scan voltage applied

to

the base of Q206 in the comparator.

b. Any particular level of voltage applied scan-voltage side represents a particular point in time (paragraph 4-58), as measured from the startof the ramp. Therefore any change in the voltage applied to the Q206

(base

of Q206) of the comparator

its

to

the

01255-1

Model 185B

base

will

(or

to

the comparator SCALE MAGNIFIER VERNIER in sec/cm TIME SCALE switch.

4-68. A voltage change of say amplifier causes the spot to shift a certain number of centimeters on the crt. Also, as described in paragraph 4-67, step b, comparator represents

4-69. Thus

pen sooner

cidence represents also cause a change curs when the ramp slope ing TIME SCALE) or when horizontal-scan voltage to the comparator TIME SCALE MAGNIFIER).

4-70. Changing scan density, however, does not change time scale because the horizontal-scan voltage

to the crt and the horizontal-scan voltage to the com-

parator are changed by the same ratio. time scale can result only from a change in the slope of the ramp signal voltage applied to the comparator with respect to the horizontal-scan voltage applied to the crt. Scan voltage as such has absolutely no effect on time scale (to check this, switch SCANNING to MANUAL, and adjust SCAN). Time scale can be expressed mathematically

as

follows:

ramp slope, attenuation crt deflection

(

where

attenuation factor

attenuated scan voltage (at comparator)

scan voltage at horizontal amplifier input

4-71. DELAY CIRCUITS.

4-72. As mentioned previously (paragraph 4-48),

the DELAY potentiometer determines the starting voltage of the ramp signal by controlling the output voltage of delay reference-voltage generator Q201Q202.A certain amount of delay DELAY sition). This delay insures will have reached the linear portion of istic before the delay (the time between input trigger and

ple)

4-73. The following facts must thinking about delay:

a.

occurs (plus

b. Any time lapse between the input trigger and the

first

cause the ramp to reach coincidence sooner

later)

in time. Thus when the scan voltage applied

is

ANY

so

sec/v

crt

deflection sensitivity

v/cm deflection

is

full counterclockwise (minimum delay po-

is

adjusted with MINIMUM DELAY, R213.

The ramp signal begins when the input trigger

a

comparator coincidence

is

attenuated (as

is

at any setting except CAL), time scale

no longer the value selected by the

at any setting except

x

this

same voltage sent to the

a

certain point in time.

method of making coincidence hap-

that from the

a

is

or

time scale in sec/cm

)

(

=

start

shorter interval of time

in

time scale. This

is

made steeper (by adjust-

further attenuated (by adjusting

a

change in the horizontal-scan

factor ) (sensitivity,v/cm

=

at

input to horizontal amplifier

that

first

coincidence occurs. Minimum

delay inherent in the circuit).

is

it

is

when TIME

X1

or

volts to the horizontal

of the ramp to coin-

is

what oc-

A

change

=

is

added even when

the ramp voltage

its

character-

first

sam-

be

remembered when

interpreted

as

delay.

its

will

in

I

Paragraphs 4-68 to 4-79

is

c. Time scale amplitude difference between the signal to the comparator and the signal to the horizontal amplifier. Differences in step-to-step amplitude of the staircase

(horizontal-scan voltage), nonlinear scan voltages,

etc, have no effect on the time scale. 4-74. Figure 4-9 shows the effect of varying the ramp

starting voltage. Unless TIME SCALE MULTIPLIER

is

on

X1,

DELAY control R212. When TIME SCALE MULTIPLIER of delay available tained by adjustment of screwdriver-adjust MINI-

MUM

or MINIMUM DELAY varies the output delay reference-voltage generator Q201-Q202, and hence the ramp starting voltage. 4-72, to avoid possible nonlinearity The exact amount of delay which will occur depends on two factors: ing voltage was made negative (by either R231, MINIMUM DELAY or R212, DELAY), and of the ramp.

4-75. DELAY/TIME SCALE MAGNIFIERRELATIONSHIP. When TIME SCALE MAGNIFIER setting except the horizontal amplifier and the comparator. tenuation signal-to-comparator and horizontal-signal- to-crt decreased which decreases the time scale on the crt. For example, with TIME SCALE MAGNIFIER displayed by the crt

is

at X1.

By means of the DELAY control, anydesired fraction of the interval selected with TIME SCALE can be viewed gardless of the degree of magnification selected, effectively the crt can be moved along the entire interval set by TIME SCALE by

operating DELAY.

4-76. Note in figure 5-17 (time base schematic diagram), and figure 4-7, that

MAGNIFIER

voltage generator circuit (Q201-Q202). This assures

that, regardless of the expansion used, the DELAY control will always have the range necessary to permit observation for the entire time selected by the TIME SCALE control.

4-77. COMPARATOR BLOCKING OSCILLATOR. 4-78. AMPLIFIER. The comparator pulse

entiated and amplified by C228-R231/232 and ampli-

fier Q207, respectively. The resulting negative spike

is

transformer-coupled to comparator blocking oscillator Q208-T203. Diode CR210 limits input to Q208 to negative pulses.

4-79. BLOCKING OSCILLATOR, These negative pulses trigger blocking oscillator Q208-T203 and a

the ramp starting voltage

is

on X1, DELAY

DELAY, R213. Adjustment of either DELAY

a

small amount of delay

is

determined by ramp slope and the

is

1)

the degree to which the ramp start-

X1,

increased, the ratio between horizontal-

at

X10, only 1/10

as

is

associated with the delay reference-

inoperative, and the range

limited to that which can be

As

explained in paragraph

is

built into the circuit

in

the start

it

inserts attenuation between

as

when TIME SCALE MAGNIFIER

Note

much of the signal

at

one time and, re-

a

part of TIME SCALE

Section IV

is

varied with

of

the ramp.

2)

the slope

is

as

is

ob-

at any

As

at-

is

viewed

is

differ-

01255-1

4-9

I

Section Paragraphs 4-80 to 4-83

IV

TRIGGER

NO

DELAY DELAY

Figure 4-9. Effects of Delay

\

I

I I

I

:

I

/FIRST

I I

I

I/

I

Model 185B

SAMPLE

I.Y-8.e

pdse of about 1.3 kseconds duration leading edge of pulse triggers three circuits:

A

pulse, taken at pin 2 of T203,

a. and fed via trigger sampling gate circuits

b. Another pulse, taken at pin 4 of T203, entiated and fed via ates sampling action in the plug-in. When viewed on an oscilloscope, this pulse often appears double, the second pulse is actually feeding back from the vertical plug-in unit.

c. Another output (pin

of the staircase voltage (paragraph 4-81). 4-80. In addition, the trailing edge of the comparator

blocking oscillator pulse gate extender multivibrator, which ramp (paragraph 4-52).

4-81.

4-82. The horizontal circuits both to deflect beam on the crtand to provide scanning potential for comparator circuit.

4-83. UNITY GAIN AMPLIFIER. V201A-Q210 constitute a unity gain amplifier. Tube V201A and transistor Q210 amplify the signal, while CR220 provides dc coupling between the two elements. R270, the Staircase Balance adjustment, sets the beginning of the horizon.ta1-scan signal plifier drive except EXTERNAL. The four types of horizon-

tal

from voltage divider R254, R255, R256, and connects

it

HORIZONTAL-SCAN CIRCUITS.

is

used on all modes of operation of horizontal

drive selected by ,3203 (SCANNING) follow:

a.

RECORD. In RECORD, S203 disconnects C240

to the grid of V201A. C240 charges slowly toward

this

comparator blocking oscillator

J1

to the sampler unit where

J1

to sampler unit where

1)

is used in the generation

is

used to reset the ramp-

in

at

is

produced, The

is

differentiated

it

is

used

in

vertical plug-inunit.

is

differ-

it

initi-

in

turn resets the

Model 185B are used

0

volts. The unity am-

to

but

+lo0

volts through R259 until voltage at junction of CR219 CR219 begins conduction, halting the sweep. The charge on capacitor C240

until SCANNING (S203) NAL. With ,3203

C240 discharges through resistor R257.

has

tor C240 as explained in RECORD, above, or

connects 5201, INPUT EXTERNAL SCAN connector,

through S203B, to comparator and horizontal amplifier

circuits,

drive these circuits. The external signal should between 0 and approximately + 12

ZONTAL POSITION approximately centered,

puts spot on left-hand edge graticule, puts spot on right-hand edge.)

except grid of V201A R255A, SCAN (MANUAL), manually control scanning.

amplifier V201A-Q210 results from the following circuit action (see figures 4-10 and 5-20):

and R259 reaches +15 volts. When

will

remain

is

set

at

RESET OR EXTERNAL, capacitor

b. RESET OR EXTERNAL. This position of S203

two uses:

c. MANUAL. Operation

d. INTERNAL. In INTERNAL, the output of unity

(1)

Prior to ceding staircase), staircase capacitor C236 discharged, comparator blocking oscillator (Q208-TZ03 which generates sampler trigger) has not yet generated the next pulse, and diode

CR215 is back-biased.

(2)

When coincidence occurs, comparator blocking oscillator Q208-T203 fires, and the resulting pulse CR215. CR215, forward-biased now, conducts, and capacitor C236 begins to charge.

1)

it

is

used to reset charging capaci-

so

that an external signal may be used to

is

start

of circuit sequence (end of pre-

is

coupled by transformer T203 to diode

to RESET OR EXTER-

volts, (With HORI-

is

similar to RECORD,

connected to center arm of

so

that the operator can

is

a staircase voltage which

this

at

+15 volts

+12

occurs

2)

it

be

0

volts volts

is

4-10

01255-1

Model 185B

Section

IV

Paragraph 4-84

(3) The voltage across staircase capacitor C236

is

increases, and

applied, through SCANNING switch S203C/D, to unity amplifier V201AQ210, increasing output of the generator by the same amount;

this

output

is

the horizontal-

scan voltage.

(4)

After

comparator blocking oscillator pulse decays, diode CR215 becomes reverse-biased again, and prevents charge on capacitor C236 from leaking off.

(5) DENSITY contrbl R255B

of

staircase capacitor C236. DENSITY per-

mits

limited adjustment of charge-path

ance, thereby determining amplitude

is

in the charge path

resist-

of

stair-

case steps by controlling amount of charge

added to staircase capacitor each time blocking oscillator

(6) The output

applied to transformer T203 in such a way

a

bootstrap action results. Thus for a given

density, the same amount

fires.

of

unity amplifier V201A-Q210

of

charge

is

that

added

to staircase capacitor C236 each time, which

results in staircase steps of equal amplitude.

(7) When voltage across staircase capacitor C236

reaches about +15 volts, reset blocking oscillator Q209-T204 pacitor. The staircase

fires

and discharges the ca-

is

thus reset and

starts

over again.

4-84. RESET BLOCKING OSCILLATOR. When the staircase voltage exceeds voltage on collector of Q209

(approximately 15 volts), diode CR217 becomes for-

ward-biased, current begins to flow through collector

of

winding fectively becomes the voltage supply for blocking cillator Q208-T204. The effect

is

transformer-coupled to the base of Q209, which

transformer T204, and capacitor C236 ef-

os-

of

this

current flow

causes blocking oscillator to fire, essentially dropping collector of Q209 to ground. The resulting current-flow through CR217 and QZOQ discharges capacitor (2236, thereby resetting the staircase. It might be

pointed out here that the amplitude of the staircase signal remains constant. The height ual step can

be

varied by adjusting R255B as mentioned in paragraph 4-83, step varying the height

ber

of steps per staircase, which changes the number

of

each step

of

each individ-

d

(5). The result of

is

to change the num-

of samples per sweep on the crt.

8

1

L'Cg38

-FEEDBACK

1

RESET

BLOCKING

OSClLL

ATOR

0209

?hi450

lo.01

=

4R2tB

-12.6VF

R267

300

IR253

13.7K

t25OVF -IOOVF

1

R255E

30K

0

tC.,

DENSITY

52038

1

HORIZONTAL SIGNAL

tIOOVF

1

t

t12.6VF

r-----

OUTWT

TIME EASE

-'SA!!

J202

I

-

J

i

R272

L

I8K

c

r

so-,

TO

COMPARATOR

AND HORIZONTAL AMPL.

.I

Figure 4-10. Staircase Generator

01255-1 4-11

Section Paragraphs 4-85 to 4-100

IV

Model 185B

4-85. OUTPUT. The output of unity amplifier V201A-

is

Q210

4-61). The path from unity amplifier the time scale VERNIER (or, when TIME SCALEvernier through Sweep Calib adjustment R285, TIME SCALE MAGNIFIER switch S201 where the staircase voltage is

and

assembly A501. 4-86. HORIZONTAL AMPLIFIER. The horizontal

amplifier amplifier. The scan voltage the amplifier, the horizontal positioning voltage to the other. The level of the positioning voltage is with R509, the HORIZONTAL POSITION control. The output of the amplifier horizontal deflection plates of the crt.

4-87.

4-88. SYNC PULSE. When CALIBRATOR ANDSYNC

PULSE

is

negative pulse. When the ramp-gate pulse (paragraph 4-40, step c) appears on its base, Q60l saturates, and

4-89.

ation. Capacitor C602 charges slowly through R604 and Q601, holding Q60l on for a time determined by R604-C602 time constant.

4-90. Before ramp-gate pulse appeared on base of Q601, CR604 was conducting and therefore presented

a

Q60l appears on its cathode, CR604 acts in different manner than an ordinary diode. Instead of immediately cutting off, reverse current flows momentarily, and the impedance low (the reverse current stored during the time the Q60l collector

+12

stops, and impedance of diode CR604 rises sharply;

because of this characteristic, diode CR604 provides very

rise pulse. During the short period between back-

bias and cut-off, CR204 produces step; diode CR603 blocks this step, and passes only the steep-rise portion of the pulse.

4-91. The pulse, thus shaped by CR604 and CR603,

is

4-92. PULSED 50-MC AMPLIFIER. During the time between pulses from amplifier Q601, the junction €260’7 and R610 holding base of Q603 slightly negative.

4-93. When amplified ramp-gate pulse appears on

Q60l collector, CR605 described in paragraph 4-90) becomes back-biased. When

fed:

a.

To one side of the comparator (see paragraph

is

through R286,

is

at

CAL, through contacts on switch S204),

attenuated

cathode follower V201B.

b. To the grid of V501B

if

S201

is

on any except the X1 setting,

in

horizontal amplifier

is

a

conventional, single-stage differential

is

applied to one half

set

is

connected directly to the

CALIBRATOR.

is

biased

very low impedance. When positive pulse from

coupled to J601, SYNC PULSE OUTPUT connector.

full counterclockwise, pulse amplifier Q60l

so

that

it

can conduct when triggered with

its

collector rises to

As

Q60l turns on, Q602 is driven into satur-

volts). Carriers are depleted abruptly, current

fast

switching action, and the result

is

slightly negative and CR605 conducts,

it

snaps off, resonant circuit T601-C610

+12

volts.

a

of the diode remains

is

supported by the carriers

is

a

small voltage

(a

diode of the same type

slightly

rising to

a

fast-

as

is

of

shock-excited the tank-circuit losses, resulting in a constant-amplitude oscillation, and a 50-mc voltage 5602, the 50-mc connector. When the sync pulse ends,

CR605 nating the 50-mc oscillation.

4-94. DC CALIBRATOR VOLTAGES. The rest of

this

-12.6 volts and ground. The level of the voltage fed to the AMPLITUDE DC OPEN CIRCUIT connector depends on the setting of S601, the CALIBRATOR AND SYNC PULSE switch.

4-95.

4-96. GENERAL OPERATION. 4-97. Figure 4-11

amplifier. The signal under investigation to the input of the vertical plug-in unit, and to Model 185B vertical amplifier via pins on connector

J1

4-98. In the Model 185B vertical amplifier, input signals are applied to cathode followers

a

V2,

Q3-Q4. Multivibrator V4 controls the differential amplifiers Thus only the signal applied to the “on” differential amplifier “off” differential amplifier blocks the signal applied to multivibrator V4.

4-99. CONTROL OF DIFFERENTIAL AMPLIFIERS. Except while switching, one plate of multivibrator V4 is explanation, assume the V4A plate

therefore diode CR1 between the plate of V4A and the bases of Ql-Q2 the positive voltage on the V4A plate bases of Ql-Q2, back-biasing their emitter-base

junctions, and Ql-Q2 are cut off.

the V4B plate tween V4B and Q3-Q4, and amplifier Q3-Q4 operates normally.

4-100. CONTROL OF MULTIVIBRATOR V4. When the plug-in unit fier, the vertical presentation switch (channel and mode-of-operation selector) controls multivibrator V4. The vertical presentation switch lock multivibrator V4 in one state or the other channel operation, or allows multivibrator V4 to freerun to provide dual channel operation. Multivibrator V4

dual channel operation, both differential amplifiers

are turned on some time during each sampling period even when the instrument sampling rate of 100 kc. To provide

display, the Model 187B simultaneously applies the

Channel the Channel B signal to amplifier VlB, Vertical deflection on the crt ence between the signal voltages.

is

circuit

(not shown in figure 4-11).

and then to differential amplifiers Ql-Q2 and

it,

positive

is

designed to free-run up to about 180 kc,

into

50-mc oscillation. Q603 overcomes

is

coupled

again clamped to a negative voltage,

is

simply a dc voltage divider, between

VERTICAL AMPLIFIER.

is

a

block diagram of the vertical

so

that

only one

is

amplified and applied to the crt. The

Circuits in the vertical plug-in unit control

and

the other negative; for purposes of

is

turned on

is

conducting. Under

is

negative, back-biasing diode CR2

is

the Model 187B Dual Trace Ampli-

this

is

At

the same time,

to

provide single-

termi-

is

applied

is

applied

V1

and/or

at

a time.

positive, and

condition,

applied to the

be-

so

is

running

A

signal to the Model 185B amplifier

is

then proportional to the differ-

at

its maximum a

differential

V1A

and

to

in

4-12

01255-1

Model 185B

-

4

OUTPUT

AMPLIFIER

v3

-

Section

Paragraphs 4-101 to 4-108

TO VERTICAL

DEFLECTION

PLATES OF CRT

IV

t

CATHODE CATHODE

FOLLOWER

VIA V2A

INPUT FROM

CHANNELA

OF PLUG-IN

4-101. TRANSIENTS. 4-102. To prevent switching transients from appear-

ing on the

brator V4

crt to blank the crt during switching time. During

sampling, pulse to amplifier V5; transients from appearing on the crt.

4-103.

4-104. The high-voltage power supply (figure 4-12) provides voltage (-2900 volts) required to operate the crt. An mately 80 kc. High-voltage transformer T301 steps up oscillator output V303 and V304 and their associated rc filters convert

to

dc. The dc voltages are applied to the crt. Regulator V301 compares output of the with +250 volts and changes amplitude of tions to oppose any high-voltage change relative to the 250 volts.

I

j

CATHODE CATHODE

FOLLOWER

VERTICAL

PRESENTATION

SWITCH

PLUG-IN

crt,

a

negative pulse generated by multivi-

is

applied to amplifier V5 and then to the

the

vertical plug-in unit sends a blanking

HIGH-VOLTAGE POWER SUPPLY.

rf

oscillator, V302, oscillates

to

a high

d

DIFFER-

ENTIAL ENTIAL

AMPLIFIER AMPLIFIER

01/02

MULTI-

IN

e---

VIBRATOR

-

Figure 4-11. Vertical Amplifier Block Diagram

this

pulse prevents sampling

at

ac

voltage which rectifies

crt

cathode supply

+=

v4

approxi-

rf

oscilla-

FOLLOWER

1L

-

DIFFER-

03/04

4

*

FOLLOWER

V2B

-

e

BLANKING

PULSE

AMPLIFIER

v5

.

1

4-108. The series regulator in each supply acts as

a

variable resistor in

A

comparison or differential amplifier senses any change in the output voltage by comparing the output against a fixed reference voltage. The amplifier then changes the resistance of the series regulator in way

that

power supplies are transistorized. Emitter followers are required between amplifier and series regulator to amplify the current to the level required to drive the series regulator.

opposes the change in output voltage.

n

BLANKING

-

b

PULSE FROM

series

AMPLIFIER

V301

PULSE

TO CRT

BLANKING

PLUG-IN

with the supply output.

BD-Y-273

INPUT FROM

CHANNEL B

OF

PLUG-IN

a

The

+250V

*

4-105. The pulses from V5 (paragraph 4-102) blank the crt to prevent undesirable transients from appearing.

4-106.

4-107. The low-voltage power supplies include one

independent supply and four dependent supplies. The

-100 volt supply

reference for the +lo0 volt and +250 volt supplies and

is

of the +12.6 volt and -12.6 volt supplies.

01255-1

crt

is

normally biased on. Blanking

LOW-VOLTAGE POWER SUPPLIES.

is

the independent supply. It

a supply voltage for the comparison amplifiers

is

TO CRT

GRID

BLANKING-

a

Figure 4-12. High-Voltage Power Supply

PULSES

Block Diagram

2

.E

..*.,

4-13

Section V Table 5-1

Model 185B

Table 5-1. Recommended Test Equipment

Instrument

oscilloscope

DC Voltmeter/

Ohmmeter

Precision DC

Voltmeter

High Voltage

DC Voltmeter

AC Voltmeter Voltage Range: 10 mv rms

Variable

Transformer

“Qpe

Required Characteristics

Passband:

Sensitivity: 0.5 Input Impedance: 10 megohms

Voltage Range: 1-300 volts Voltage Accuracy: 3%

Input Impedance:

Resistance Range:

Voltage Range: 10-300 volts Input Impedance: at least 10 megohms Accuracy:

Voltage Range: 3000 volts Input Impedance: 12,000 megohms Accuracy: 8%

Input Impedance: Accuracy:

Output Voltage: 103-127 volts

(206-254 volt

wired for 230-volt operation)

Output Current: 5 amps (2.5 amps

for 230-volt operation)

dc

1%

10%

to

if

10 mc

to

100 volt/div

(with probe)

at

least

1

ohm

megohms

at

least

oscilloscope

10 megohms

to

20

1

megohm

Use

Observation of waveforms

General voltage and

sistance measurements

Set

low voltage power

supplies

Measure high voltages

Measure low voltage

power supply ripple

Vary line voltage General Radio

re-

Model

AN/USM-lOBA

@

150A

@

160B

@

170A

($9

175A

ME-26A/U

@

410B

@

412A

9

412A

TS-520/U

($3

410B with

@

459A

ME

-3

OA/U

@I

400D

Type

WlOMT3A

.

Signal Generator Frequency Range: 10-100 mc

Output Amplitude: 15-500 mv Frequency Accuracy: 0.1%

Signal Generator

Pulse Generator

Delay Line

Sync Take-Off

Plug-In

Amplifier

bad,

50-Ohm

-0

Frequency: 1000 mc Amplitude: 20.7 mv

Rise

Time:

Amplitude: at least 50 mv Delay: 120 nsec

Passband:

~

hput Impedance: 50 ohms

1O:l ratio Divider

I

Compatible with 185B

50-ohm Type

Qdapter to 187B Probe

Type

less

500

N

connectors

than 10 nsec

mc

N

connector

-

50-ohm

Check frequency calibrator

accuracy and trigger sensitivity

Trigger sensitivity

Set minimum delay

Provide fixed delay

Split input signal into

two

~~ ~~

signals

Attenuate sync pulse

amplifier system

Terminate 50-ohm test

Signal

To insert probe in

50-ohm system

AN/USM-44A

@

608D

I

@612A

@J llOOA

($3

185A-76A

@

187B-76C

@

908A

@

187B-76E

01255-1 5

Model 185B

Paragraphs 5-1 to 5-20

Section

V

SECTION

MAINTENANCE

5-1.

INTRODUCTION.

5-2. This section provides maintenance and service information for Model 185B oscilloscope. Included in

this

section

to

verify proper instrument operation. The section also includes recommended test equipment, troubleshooting, repair, and adjustment procedures.

5-3.

5-4. Table 5-1 to complete the maintenance instructions in tion. Instruments other than those recommended may

be

used, provided their performance meets the basic

requirements given

5-5.

5-6. CLEANING THE AIR FILTER. 5-7. Inspect the

before

a. Remove filter from instrument

it

in warm water and detergent.

b. Dry the filter thoroughly and coat

adhesive,

search Products Company, Inc. This adhesive comes

in “Handi-Koter” sprayer cans and most heating supply stores or from your authorized Hewlett-Packard sales representative.

5-8. GENERAL MAINTENANCE. 5-9. Other than periodic cleaning of the air

as mentioned above, the Model 185B requires no spe-

cial preventive maintenance. We do suggest, however, that low pressure air dust out

5-10. CABINET REMOVAL.

5-11. To remove the Model 185B cabinet, proceed as follows:

a. Remove the plug-in unit.

b. Set instrument on

Be careful of the probe clips.

c. Remove four screws at rear of cabinet.

d. Lift cabinet up and off the instrument.

5-1

2.

5-13. The troubleshooting procedure

two categories:

the trouble

the instrument, and which trouble

is

a performance check which may

TEST INSTRUMENTS REQUIRED.

lists

test

in

table 5-1.

equipment

that

is

PERIODIC MAINTENANCE.

air

filter regularly, and clean

it

becomes dirty enough to restrict air flow.

rear,

it

with filter

We

recommended Filter Coat No.3 from Re-

is

available from

be

used to blow any accumulated

of

the instrument every

its

TROUBLES H OOTl

1)

system troubleshooting,

is

associated with a particular section of

2)

is

located within a particular section,

sectional troubleshooting, in

front-panel draw handles.

N

0.

six

months or

is

divided into

be

used

required

this

sec-

and wash

filter

so.

in

which

it

V

5-14. Since Model 185B cannot function without vertical plug-in unit, system troubleshooting on the assumption that a Model 187A or 187B Dual Trace Amplifier unit tional troubleshooting information on the plug-in unit, refer to the instruction manual

5-15. SYSTEM TROUBLESHOOTING.

5-16. System troubleshooting consists of observing indications on the crt and associating the indications with a particular section or circuit. indications are listed in table 5-2 along with any necessary steps for clarification. If erating but does not meet all specifications, refer the appropriate section of the performance check,

paragraph 5-67, and check the particular instrument

operation in question.

5- 17. SECTIONAL TROUBLESHOOTING. 5-18. MAIN VERTICAL AMPLIFIER. Since the ver-

tical amplifier consists of balanced amplifier circuits,

trouble other than open tube heaters will usually cause an unbalance. If an unbalance nels, check circuit of V3. Ifunbalance nel only, short input of faulty channel to ground and check voltages throughout the channel.

Troubleshoot vertical amplifier with ver-

tical

plug-in unit installed. Otherwise multivibrator V4 shooting more difficult. However, traces appear on screen near center when vertical plug-in indication that trouble

5-19. TRIGGER CIRCUIT. Troubleshooting the sync circuit

forms throughout the circuit are shown in figure 5-11

opposite the schematic. 5-20. The following

Model 185B trigger circuit.

sure that all diodes and transistors are mountedproperly on etched circuit board and that all power supply voltages are within specifications (paragraph 5-47).

MODE full counterclockwise, collector voltage should be approximately -12.5 volts, and should increase to

-5 volts as MODE

test

tunnel diode CR116.

voltage across CR116 with dc electronic voltmeter.

The anode to cathode voltage should be about 10 mw.

is

best

a.

Measure voltage at collector of Q104. With

indicates that bias current

b. Turn MODE full counterclockwise and measure

is

installed. However, for sec-

for

the plug-in unit.

the

instrument

is

common to both chan-

Note

will

free run and make trouble-

is

removed,

is

done by observing waveforms. Wave-

will

be helpful in troubleshooting

is

rotated to full clockwise. This

this

in

the plug-in unit.

First., of course, make

is

being supplied to

is

A

number

is

in one chan-

if

two

is

a good

based

is

op-

of

to

a

01255-1

5-1

Section Paragraph 5-21

V

Model 185B

Table 5-2. System Troubleshooting

Indication

Nothing visible on crt

with BEAM FINDER pressed

Vertical unbalance, but

trace on screen when BEAM FINDER pressed

No vertical deflection

from either channel but sweep mately centered

No

vertical deflection from one channel, but operation of other channel

Same channel on screen

regardless of channel selected

Vertical troubles on

per-sample basis (vertically elongated samples, etc)

Hash on screen (no crt

blanking during sampling or chopping)

is

approxi-

normal

is

Action

Check low voltage power

supply, vertical amplifier output stage (V3), horizontal amplifier V501, high voltage power supply, and crt in

that order.

V1

7

to

is

of

Model

and V2

eachver-

If

present

If

Short grids of

2

(pins

tical amplifier input

stage)

vertical unbalance re-

mains, check vertical

amplifier. If trace

appears on screen check plug-in unit.

Check V3 and V4 in ver-

tical amplifier, plug-in unit.

Check input

185B from faulty channel of plug-in with a sig-

nal

If

check plug-in unit. signal is present, check

vertical amplifier.

Check multivibrator V4

in vertical amplifier

Check plug-in unit

Check Peaking Adj in

v3

Check amplifier V5

Check blanking circuitry

and

to

ground.

applied to channel.

no signal

No trace but spot

screen and VERTICAL POSITION and HORIZONTAL POSITION controls operate

No trace but

visible (BEAM FINDER

may have to HORIZONTAL POSITION control tive but VERTICAL

POSITION

Sweep

free

MODE set and no trigger signal applied

Operation normal on

trigger repetition rates below 100 kc, faulty on trigger rates above 100 kc

a

Horizontal unbalance

Horizontal troubles on

per-sample basis (horizontally elongated samples,

Excessive noise and

jitter which appears sinusoidal trigger repetition rates

is

spot

is

be

pressed);

is

effec-

is

not

runs with

to

TRIGGER

etc)

at

certain

Action

:heck

on

reset

oscillator Q209, unitygain amplifier V201A/ Q210 in time base

Check sync circuit Check time base

circuit

Check blocking oscilla-

tor Q106/Q107 in sync circuit, comparator blocking oscillator Q208 in time base.

Check Q104, Q105

Check hold-off multivi-

brator V101/V102

sync circuit

Check horizontal

amplifier

Check time base circuits

V201A and Q210, diodes CR215, CR217 and Q205

Check low voltage power

supply

Be sure trigger

overdriving input

blocking

is

not

“two

is

If

if

does

to

full

the the

c. Slowly rotate MODE clockwise. The anode

cathode voltage should increase to about 60 mv and

is

then jump to about 470 mv when MODE o’clock’’. Continue turning MODE until clockwise. The voltage should rise to about 500 mv.

d. Turn MODE full counterclockwise. The cathode

to

anode voltage should jump back to 10 mv. anode to cathode voltage voltage does not change MODE full counterclockwise and flip power switch off and on two or three times. not change to about 10 mv, CR116 or out of specifications, and should be replaced.

5-2

is

as

about

MODE

500

If

voltage

is

near

it

mv, and

is

rotated, turn

still

either defective

5-21. If, after completing the above procedure, the

will

instrument

a.

Open the circuit loop by lifting C146

tion of R175 and L112 (see figure 5-1).

b.

Set controls on

lows (use 75-ohm source):

(1)

Attenuation

(2)

Amplitude

(3)

Frequency to 30 kc

c.

Using clip leads, connect equare wave generator

to

capacitor and to ground

not free

at

1

square

0

db

volt

run,

proceed

wave generator

as

shown in figure 5-1.

as

follows:

at

the junc-

01255-1

as

fol-

Model 185B

Paragraphs 5-22

Section

to

5-28

V

A103

-TRIGGER

Figure 5-1. Driving the Trigger Circuit

CIRCUIT BOARD

TO

GROUND

LO-S-5Sl

should

left,

5-26. on the ramp-gate extender multivibrator emitter of Q103 and the emitter end of resistor R147 from circuit board' (see paragraphs 5-34 and 5-37).

The Model 185B should operate on the four fastest time-scale ranges. If gate extender

5-27. sync pulse circuit consists of a pulse extending amplifier Q60l/Q602, a 50-mc oscillator Q603 and shaping diodes CR604/605. The waveforms for this section are shown on figure 5-23. If both time calibrator and sync pulse are faulty, check Q60l and Q602. If only the sync pulse

If

CR605 and Q603. 5-28. HIGH-VOLTAGE POWER SUPPLY. Measure

voltages supplied

be

less

than about 1 cm/sec. If spot drifts

check CR215;

If

time-base circuits

all

ranges and the cause

TIME

CALIBRATOR. The time calibrator and

the fault

Be very careful when measuring highvolt-

Use

ages. measurements.

if

spot drifts right, check CR217.

are

operating erratically

is

not apparent, disable

by

it

does, trouble in the ramp-

is

indicated.

is

faulty, check CR604.

lies

only in the time calibrator check

to

the crt.

WARNING

equipment suited for high-voltage

lifting the

two

The square wave cannot Q107. The observed voltages should appear essentially

as

Btor

scribed previously. function properly when driven from the square wave generator, but the tunnel diode CR104, CR124, and CR125 for continuity and proper

polarity.)

5-22. Count Down Circuit.

not trigger on the high frequency count down circuit, turn TRIGGERING to HIGH FREQUENCY and measure voltage at anode of CR120. This voltage should

be

with and

10-mc sine wave, approximately 300 mv peak-to-peak.

If

voltage served, change CR120 (read paragraph 5-36 before attempting

6-23. TIME BASE. Troubleshooting the

best

5-24.

ates normally, not Qiggered, V201A (excessive grid current) may

be

between samples. Set DENSITY and carefully check waveform at Q210 collector for

sag

shown in figure 5-2. (The blocking oscil-

and hold-off multivibrator should operate as de-

about

200

a

Model 150A/151A

an

done

If

mv. Observe

AC-21C probe. The waveform should

is

correct, and the sine wave cannot

to

replace tunnel diodes).

by

observing waveforms

comparator blocking oscillator Q208 oper-

but

removing charge from staircase capacitor, C236,

between samples.

be

traced through Ql06 and

If

all

parts of the trigger circuit

will

If

the Model 185B

signal

or

a Model 160A oscilloscope

at anode of CR120

(see

reset

blocking oscillator Q209

full

counterclockwise

not reset, check

will

be

ob-

time

base

is

figure

5-15).

is

crt

a.

If

receiving a faulty blanking signal, replace crt.

b.

If

cillator V302

crt

cathode supply causes a greater output from the

rf

oscillator and therefore a more negative output from the crt grid supply, grid supply both crt supplies are excessively high, cessively low, check regulator V301.

a

voltages are normal, and the crt

high voltages are incorrect, check that

is

oscillating. Note that a fault in

whereas

has

no effect on the cathode supply.

a

fault

or

in

the crt

both

is

rf

not

os-

the

If

ex-

n

CATHODE

BASE

OF

CR119

0107

t

W-S-319

5-25.

If

bere

is

horizontal motion or elongation

Individual samples, stop triggering

drift

and note horizon'tal

0

1

255-

1

of spot. The drift

of

oscilloscqpe

rate

of

Figure

5-2. Trigger Circuit Waveforms

5-3

I

Section Paragraphs 5-29

V

to

5-35

Model 185B

Table 5-3. Resistance

supply

-100 volt

12.6 volt

+

6.3 volt

+

12.6 volt

+

100 volt

+

250

volt

*

Note: Readings differ due to diode, transistor action and applied voltage polarity from ohmmeter.

Do not such adjustment adjustment of high voltages affects the sensitivity of the crt and makes necessary the readjustment of vertical and horizontal gain, frequency response and time scales.

5-29. LOW-VOLTAGE POWER SUPPLIES. When checking low-voltage power supplies, check the -100

volt supply

the

other supplies in the following order:

+lo0 volt, +250 volt. The +12.6 volt supply may

checked in any order. The following describes method of checking the +250 volt supply; a similar

procedure may be used for the other supplies.

a.

Check F402.

+250 volt line

reset

first,

to

Color Code

violet vio/wht brn/wht brown red/wht red

Note

High Voltage Adj R306unless

is

clearly indicated, The

for

it

affects all supplies. Check

If

blown, check resistance from

ground (see table 5-3).

412A Range

RXlK RXlOO

RX1 RX1 RXlK RXlOK

-12.6 volt,

to

Ground (values may vary 25%)

412A Reading

750

ohms

50

ohms

*

0.5

ohm

1.0 ohm 1600 ohms

5000

ohms

(a)

from -100 volt, -12.6 volt, or +lo0 volt supplies. +250 volts and -100 volts. +lo0 volts

-100 ;rolts and

-12.6 volts are referenced

(b)

(c) Check capacitors throughout supply. Check C402, C403, and C404

be

5-30.

a

5-31. ACCESS

5-32. Figure 5-3 shows necessary disassembly for replacement of power transistors or fan motor. Pro-

ceed

REPAIR.

FAN MOTOR.

as follows:

~

410B Range

Check

Check for weak or defective transistors.

to

TO

RXlOO RXlO RX1 RX1 RXlOO RXlK

see

if

excessive ripple

is

referenced

-12.6

volts.

first.

POWER TRANSISTORS AND

410B Reading

750

ohms

150 ohms

0.5

ohm

1.0 ohm 1600 ohms

5000

ohms

is

to

+lo0 volts

is

referenced

+12.6

volts and

to

-100 volts.

*

.

cominfg

to

b.

Check transformer output.

Take

care

c.

Check supply output. Note whether

low, or contains excessive ripple. Typical ripple

less

than 8 mv peak-to-peak, when the instrument

not triggered or free-running.

(1)

Output Too High. Disconnect and note any change in supply output. If output decreases, check Q403 and Q404. If no change, check Q401 and Q402.

Ou

(2)

(3)

~

I

5-4

ut Too Low. Disconnect collector lead of

bany change in supply output.

output increases, check Q403 and Q404. change, replace Q404 collector lead and check

Q401 and Q402.

Note

The voltage changes involved may If

so,

alternately connect and disconnect the

lead in question while observing voltmeter.

Excessive Ripple. and excessive or insufficient loading of sup-

plies can cause excessive ripple.

Low

base

or

high line voltage

it

is

lead ofQ402

be

small.

high,

is

If

no

plifier tubes from their sockets.

a.

Remove cabinet.

b. Remove eight screws holding fan shroud

chassis.

c.

Rotate shroud slightly transistor, and remove shroud assembly from the instrument.

5-33. Replacement procedure

above. Install shroud with blank heat sink slot

9

o’clock as viewed from rear of instrument.

5-34. REPLACEMENT OF SEMICONDUCTORS. 5-35. Excessive heat can destroy semiconductor de-

vices. When soldering or unsoldering transistors or

diodes, place a heat

lead of component between

is

heat

ground or ground body of soldering iron

leakage current from damaging component.

applied.

not

In

Note

to

dislodge the vertical am-

to

rear

to

allow clearance for

is

the reverse of

the

at

sink

such as long-nose pliers on

its

addition, isolate oscilloscope from

body and point

to

prevent

01255-1

which

Model

185B

Paragraphs

5-36

Section

to

5-41

V

I

Figure

5-36.

TUNNEL DIODE REPLACEMENT. Tunnel diodes are more sensitive conductors. Particular

to

care

5-3.

Disassembly for Power Transistor Replacement

heat

than

is

other

required in their

semi-

replacement.

5-37.

SERVICING ETCHED CIRCUIT BOARDS.

5-38.

GENERAL. Component miniaturization

instrument

has

resulted in the use of a board with

in

this

conductor material on both sides. Good conductivity

between sides

has

been assured by plating the inside of component mounting holes. This method of construction presents the need for new techniques in etched circuit board repair.

5-39.

Proceed

a.

Using a clean soldering iron,

transfer

to

one lead of component

as

follows:

so

that

good

is

obtained, apply heat (near circuit board)

to

be

removed. Repeat for

heat

other leads.

CAUTION

AVOID EXCESSIVE HEAT.

40-watt

cause copper circuit to

a

soldering iron. Excessive heat

heat

sink

(e.g., pair of long-nose pliers)

lift

Use

a

from board.

25-

to

will

Use

between soldering iron and component. See paragraph

5-36

for special techniques in

replacing tunnel diodes.

b.

Reheat solder around holes and quickly insert a toothpick to clean holes in preparation for inserting new component. metallic object

NOT use an awlor

to

ream the hole. Doing

similar

so

sharp

may re-

DO

move plating from hole.

c.

Preform new component leads actly.

ing

Insert new component carefully, without forc-

it.

d. Resolder by applying heat

component

of board.

Use

side

assure a good connection. Clean off excess

5-40.

When heavy, multi-lead components such

tube

or

transformer sockets must be replaced, good practice ponent pins one

is

to remove component by clipping the com-

by

one and unsoldering the pins

to

fit

holes ex-

to

component lead on

just enough solder

flux.

to

as

individually.

5-41.

CRT REPLACEMENT.

WARNING

Handle plastic face

a.

Remove instrument cabinet.

b.

Remove four mounting screws from bezel, and

crt

with care. Wear gloves and

mask

or goggles.

remove bezel and graticule.

01255-1

5- 5

Section Paragraphs 5-42

V

to

Model 185B

5-49

Reference

Designator

V3 05

V401 CR413

CR410 CR407

Q1

Q2

v1

Table 5-4. Adjustments Following

Function Ad justment

Cathode-Ray

-100 Volt Reference

-100 Voltage-Dropping Diode

-12.6 Volt Reference Diode

+

12.6 Voltage-Dropping Diode

Amplifier

Cathode Follower

Tube

Tube,

Transistor, and Diode Replacement

Astig Adj (R312)

"A"

Gain

(R6)

"A"

Bal (R4) c'B'' Gain (€724) I'B" Bal (R26) Peaking Adj (C7)

Trace

Horiz

Time Scale Adjustments

+

"A" "A"

Intensity

Gain (R503)

-100 V Adj (R468)

-12.6 V Adj (R457)

12.6 V Adj (R443) Cain (R6)

Bal (R4)

Bal(C8)

5L51 5-53 5-53 5 -53 5-53

5-56 5 -62 5-63

5 -47

5-47 5-47 5-53

5-53

€8

Q11

v2

Q60l CR604

Note: Replacement of almost any component in the

requires adjustment

c. Loosen

and socket. Do not remove screws

d. Remove socket from

e.

Slide

5-42. To install a replacement crf reverse above procedure. When crt on, obtain alignment with horizontal lines on graticule. essary, loosen clamp on crt base and rotate the tab on socket to align trace with graticule lines. If instrument trace with

5-43. AATUSTMENT FOLLOWING REPAIR.

5-44. Table 5-4 replacement of transistors, and

a

follow-up adjustment are not

out component associated with an item

is

replaced, check adjustment for listed item.

two

crt

forward

a

free-running trace, and check trace

has

SCALE

lists

a

diodes

Amplifier Amplifier Cathode Follower

Pulse Amplifier

Pulse

Shaper

screws holding clamp on

crt

base.

aut

of instrument

is

installed, turn instrument

Diode

of

Time Scales and Minimum Delay.

crt

or

clamp.

If

crt

an internal-graticule crt, align

panel control.

adjustments required following

tube,

transistor,

which can be replaced with-

or

diode.

listed. listed

Tubes,

If another

in the table

base

nec-

by

"B"

Gain

(R24)

"B"

Bal (R26)

Pulse Delay (R611)

trigger

5-45.

5-46. A condensed (table 5-6) follows the detailed procedures. The table

is

justment procedures and no longer require thedetails of long procedures.

5-47. LOW-VOLTAGE POWER SUPPLIES.

5-48. The low-voltage power supplies stable and seldom will require adjustment voltages are regulated and within about nominal values, avoid adjustment. Be sure toaccount for measuring voltages.

5-49. The -12.6 volt supply above, for tude calibrator. Keep output of

1%

or

time-base circuits

ADJUSTMLNTS.

test

and adjustment procedure

for those who

any

possible inaccuracy in the voltmeter when

are

thoroughly

is

this

supply determines accuracy of nmpli-

Of

-12.6 volts.

5-53 5-53

5-66

5 -63 5-64

familiar

an exception

this

with

3%

supply

the

are

quite

If

of their

to

within

ad-

the

5-6

01255-1

Model 185B

Note

Following adjustment of any supply except

the

-12.6 volt supply, check adjustments

table

listed in

5-50. When adjustment plies in the following order: -100, -12.6, +12.6, and +250. You can measure voltages at any convenient point. Table 5-3 indicates the wire color code associated with each supply, and figure 5-12 indicates

the location of each adjustment.

5-51. HIGH-VOLTAGE POWER SUPPLY.

5-52. Adjustment of the high voltage flection sensitivity, intensity, and astigmatism. Check horizontal and vertical gain following any adjustment of high voltage. Intensity and astigmatism adjust-

are

ments

a.

heater winding on power transformer

b.

volts as read on voltmeter.

c.

and position trace in center of crt.

d. Set INTENSITY

R320 (figure 5-6)

e.

TENSITY

f.

for

small,

5-53. VERTICAL AMPLIFTER.

5-54. GAIN AND BALANCE.

a.

NAL, DENSITY full clockwise, and CALIBRATOR

-200.

b.

R61 and C1 (channel A input) and R63 and C5 (channel B input)

included in

Be

careful when measuring high voltage.

Use

equipment suited for high-voltage meas-

urements.

make

adjustments

Connect voltmeter

Set

High Voltage Adj R306 (figure 5-6) for -2800

Set

MODE

Set

SCANNING

to

Adjust FOCUS and Astig Adj R312 (figure 5-6)

round spot.

Set MODE

Remove Model 187A/B and connect function of

to

5-4 under V401.

is

necessary, adjust the sup-

this

procedure.

WARNING

Use

an

insulated screwdriver

in

this

procedure,

to

either terminal of

to

FREE RUN, SCANNING

to

9

o'clock and adjust Int. Limit

to

just extinguish trace.

to

MANUAL, and increase IN-

make spot visible.

to

FREE RUN, SCANNING

ground with a clip lead.

affects

(see

figure 5-10).

crt de-

to

INTER-

+loo,

to

crt

FINE,

to

Paragraphs

g.

Remove ground from channel B input and con-

nect junction

h.

Adjust Channel B Gain, R24,

deflection.

5-55. PEAKING ADJUST (C7).

a.

Set MODE

NAL and DENSITY

b. Place Model 187B channel selector in the

position, and adjust VERTICAL POSITION controls

to

separate traces approximately 10 cm.

c.

Adjust

tails

on samples.

5-56. TRACE INTENSITY BALANCE (C8).

a.

Set

NAL, and DENSITY

b.

Place

position, and separate traces slightly with VERTICAL POSITION controls.

c. Adjust C8 (figure 5-6) for equal intensity

both traces.

5-57. SYNC CIRCUIT. 5-58. FREE RUN ADJUST (R157).

a.

Set SCANNING

clockwise, and MODE

b.

Adjust R157 (figure 5-9)

just

trace

5-59. TIME BASE. 5-60. PULSE LENGTH (R236).

a.

Set MODE

NAL, and DENSITY full clockwise.

b.

Observe collector waveform of Q208 on the

oscilloscope.

c. Adjust pulse length, R236, (figure 5-9) for pulse width of 1.3 microseconds points of positive-going pulse.

5-61. STAIRCASE BALANCE (R270).

to

calibrator input.

to

F'REE RUN, SCANNING to INTER-

full

counterclockwise.

C7 (figure 5-6) for minimum vertical

MODE

to

F'REE RUN, SCANNING

full

clockwise.

Model 187B channel selector in

to

INTERNAL, DENSITY

to

approximately 2 o'clock.

so

appears.

to

FREE RUN, SCANNING to INTER-

at

the

Section V

5-50

to

5-62

to

obtain 4-cm

A

&

to

INTER-

A

&

on

full

that horizontal

half

amplitude

B

a

c.

Adjust Channel A Balance, R4, (figure 5-6) and

to

Channel B Balance, R26,

d.

Remove ground from channel A input and con-

nect junction

e.

Adjust Channel A Gain, R6,

deflection.

f.

Disconnect channel A input from calibrator and

jumper to ground.

01255-1

to

calibrator output.

center both traces.

to

obtain 4-cm

a.

Set SCANNING

ZONTAL POSITION

b. Set SCANNING

counterclockwise, and adjust Staircase Balance R270

(figure 5-9)

5-62. HORIZONTAL AMPLIFIER GAIN (R503).

a.

Set SCANNING

RUN, DENSITY

so

first

full

clockwise.

to

EXTERNAL and adjust HORI-

so

spot

is

at

left

edge of graticule.

to

INTERNAL, DENSITY

dot

is

at left edge of graticule.

to

INTERNAL, MODE

to

full

FREE

5-7

Section Paragraphs 5-63

V

to

5-65

Model 185B

b. Adjust Horizontal Gain R503,

trace length of approximately 5-63. TIME SCALE ADJUSTMENTS.

a.

Connect either vertical probe

CALIBRATOR output and adjust vertical SENSITMTY

for

convenient display.

Note

Precheck CALIBRATOR AND SYNC PULSE accuracy in paragraph 5-65.

b.

Set MODE NAL, DENSITY wise, Time Scale VERNIER

c. Set TIME SCALE

MAGNIFIER to 100.

d. Set DELAY

taining the 50-mc

e.

Adjust R285 (figure 5-9) for 1 cycle/cm.

f.

Set TIME SCALE MAGNIFIER

SCALE for 2 cycles/cm.

TIME

to

g.

Change TIME SCALE MAGNIFIER

to

5

h. Display should show 20 cycles

i.

Change TIME SCALE MAGNIFIER

SCALE

to

FREE RUN, SCANNING

full

clockwise, DELAY counterclock-

to

2 pSEC/CM, TIME SCALE

as

far clockwise

signal

2

pSEC/CM, and adjust Time Scale VERNIER

~SEC/CM.

to

io

~SEC/CM.

across

11

cm.

CAL.

(figure

5-5)

to

the 50-mc

to

as

possible, main-

the

full

to

X20,

to

X50, SWEEP

in

10 cm *5

to

XlOO and

for

INTER-

screen.

TIME

mm.

a

91858

OSCl LOSCOPE

I

F

NOTE:

IF

187A

IS

USED,

CHANGE 1878-76E TO I87A-76E TEE

I

Figure 5-4. Minimum Delay Measurements

5-64. MINIMUM DELAY.

a. Connect equipment b.

Set

TIME SCALE to 100NSEC/CM, TIMESCALE MAGNIFIER LAY

full

MAL, vertical SENSITIVITY

c.

Adjust Model 213A sensitivity and adjust Model 185B MODE and STABILITY for stable pattern.

d. Adjust R213, Minimum Delay (figure 5-9)

pulse

rise

to

X10,

counterclockwise, TRIGGERING to NOR-

occurs 2 cm from

as

shown in figure 5-4.

SCANNING

to

start

to

INTERNAL, DE-

100 MILLIVOLTS/CM.

full

of

trace.

,o-s.aas

clockwise

a

so

j. Display should show 20 cycles in 10 cm i5 mm.

k.

Set

Time

midrange, and adjust all other ranges following conditions of table 5-5.

Table 5-5. Time Scale Adjustments

TIME

SCALE

2

pSEC/CM

5

~SEC/CM

10 pSEC/CM

1

pSEC/CM

D.

5 pSEC/CM

200

NSEC/CM

100

NSEC/CM

50

NSEC/CM

20

NSEC/CM

10

NSEC/CM

10 NSEC/CM

5-8

Scale VERNIER

djustment,

see

MAGNIFIEE

XlOO XlOO XlOO X5

0

X50 x10 x5 x5

x1 x1

IC2

to

CAL, DELAY

figure

5-9)

R285 Check Check C2 07 C209 c211 C2 13 C2 15 C2 17 C219 Check

Display

:ycles/cm:

to

@

&I658

NOTE:

IF

I87A

IS

USED, CHANGE 1878-76E

Figure 5-5. Calibrator Instrument Setup

5-65. CALIBRATOR AND SYNC PULSE.

a. Connect equipment as shown in figure 5-5.

b. Set CALIBRATOR

NING

to

INTERNAL, DENSITY

SCALE

X5,

187B channel selector to 50

to

100 NSEC/CM, TIME SCALE MAGNIFIER

DELAY full clockwise, TRIGGER

MILLIVOLTS/CM.

full

L

counterclockwise, SCAN-

full

A

&

B, SENSITIVITY

6080

SIGNAL GENERATOR

b

TO

187A-76E TEE

Lo-a-on

clockwise, TIME

to

NORMAL,

01255-1

to

Model 185B

Test

Required

Equipment

Table 5-6. Condensed Test and Adjustment Procedure

Procedure

Adjustment

Section

Paragraph 5-66

Notes

V

Time Scale

Ad

j

Minimum

Delay

None

Delay line

1201113, $0-ohm

@

llOOA Probe Tee 50-ohm

($9

187B-76E Termination

50-ohm @908A Sync Take -Off 50-ohm

@

185A-76A

Pulse Generato.

rise

10-ns

@213A

time

Time

Scale Magnifier Adjust

2

pSEC/C,M

1

FSEC/CM

0.5

~SEC/CM

200

NSEC/CM

loo

NSEC/CM

50

NSEC/CM

20

NSEC/CM

I

~ONSEC/CM

:onnect pulse generator

to

trigger INPUT and through delay line to vertical channel of

185B/187A/B. Set TIME

SCALE

TIME SCALE MAGNIFIER to XlO, and DE LAY full counterclockwise

to 100

NSEC/CM,

I

XlOO

X5

0

X5

0

x10 x5

x5

x1

idjust MINIMUM

DELAY (front panel) rise time occurs

2

of trace.For close

approximation see

note column. same

and MAGNIFIER

settings.

C2 17

so

cm after

TIME

cy/cm

pulse

start

SCALE

For

Use

Precheck 50 MC

calibrator accurac]

A

close approximation can be made by connecting the

vertical probe

to 50-mc connector and ad-

justing delay

so

nonlinear

portion of 50-

mc signal

(first

few

cycles)

off screen

is

just

Sync Pulse

Position

50 MC

Ad just

c.

Set signal generator output for 350 mv at 50 mc

(use calibrator on signal aenerator to insure exact

frequency).

d. Adjust MODE and STABILITY for stable display.

e.

Adjust C610 (figure 5-6) to make CALIBRATOR

frequency within

If

CALIBRATOR

source for sweep times set CALIBRATOR

to 50 mc *250 kc.

1O:l

Divider

@

187B-76C

Signal

Generator

50

mc

@

606A

or

608D Probe Tee Connector 187B-76E

-I

1

mc of signal generator frequency.

Note

is

to

be used as calibrating

lonnect vertical probe through

1

divider to SYNC PUlSE

10: OUTPUT. Free run 185B, set TIME SCALE to 100 NSEC/

TIME

CM, FIER to X10 and DELAY counterclockwise

'onnect one channel at 187B

to

50-mc connector and the

other through tee connector

to

signalgenerator. Connect spen end of trigger INPUT

SCALE MAGNI-

tee

to

the

as

signal

is

3 cm after

so

start

@

of trace.

606A and

608D have internal crystal calibrators

*I%

hdjust R611

rise of pulse is 3 cm after of trace

Ldjust C610 to

make calibrator frequency same

185B

5-66. SYNC PULSE POSITION (R611).

SYNC PULSE output through a 187B-76C.

to FREE RUN, TIME SCALE to 100 NSEC/CM, TIME SCALE MAGNIFIER to X10, DELAY full counterclock-

wise, and SCANNING to INTERNAL full clockwise.

of sync pulse

generator

frequency

a. Connect either vertical amplifier probe to the

b. Set SENSITIVITY to 100 MILLNOLTS/CM,MODE

c. Adjust Pulse Position R611 (figure 5-2)

so

rise

01255-1

5-9

Section Paragraphs 5-67

V

to

Model 185B

5-75

5-67.

5-68. TIME CALIBRATOR.

set signal generator to 50 mc i250 kc.

vertical SENSITIVITY for convenient display.

signal generator frequency.

5-69. SYNC PULSE.

termination (908A) to SYNC PULSE output.

check:

5-70. AMPLITUDE CALIBRATOR. 5-71. Connect voltmeter (412A) to CALIBRATOR

output. Voltages measured on each range should within the tolerances listed in table 5-7.

PERFORMANCE CHECK.

a.

Connect equipment as shown in figure 5-5 and

b. Set channel selector on 187A/B c. Adjust MODE, STABILITY and time scales and

d. Calibrator frequency must

a.

Connect tee connector (187B-76E) and 50-ohm

b. Connect one vertical probe to tee connector and

Amplitude - at least 1-1/2 volts

-

2

Rise Time Width

ns or less

-

approximately 5

be

to

A

within 1 mc of

ps

&

B.

be

g.

Switch TIME SCALE

as

DELAY

h

i.

to

midrange and following table 5-8, check balance

of sweep time ranges for

5-73. 5-74. Connect one vertical input

TOR output,

that

cycle displayed. 5-75. TRIGGER SENSITIVITY.

a. Set TRIGGERING

(1)

(2) Set TIME SCALE

(3)

b.

(1)

in step b.

Display should show 20 cycles in 10 cm *5 mm.

Set

Time Scale VERNIER

MINIMUM

period of second cycle

Connect put and to vertical input probe Apply

Trace should appear of MODE and STABILITY controls.

Set

TRIGGERING to SENSITIVE.

Repeat paragraph 5-75, step

peak-to-peak signal from generator.

DELAY.

set

DELAY counterclockwise, and note

signal

a

300-mv peak-to-peak, 100-mc signal.

to

10 pSEC/CM and adjust

to

CAL and DELAY

a

IO-cm display *5 mm.

to

50-MC CALIBFU-

is

equal-to period

to

NORMAL.

generator (608D)

as

to

100 NSEC/CM.

with

proper adjustment

to

trigger

infigure 5-8.

a,

using 30-mv

of

last

in-

I

CALIBRATOR range 20 100 200 1000

Tolerance 0.6 3 6 30 mv

5-72. TIME SCALE.

a.

Connect one vertical probe

TOR output.

b. Set TIME SCALE MAGNIFIER SCALE to adjust DELAY as far clockwise as possible and maintain 50-mc signal across full trace.

c.

d. Adjust Time Scale VERNIER 4 cycles in 10 cm.

e. Switch TIME SCALE DELAY as in step b.

f.

2

pSEC/CM, and free run Model 185B and

Display should show 10 cycles in 10 cm *5 mm.

Display should show 10 cycles in 10 cm &5 mm.

to

50-MC CALIBRA-

to

5 pSEC/CM and adjust

MV

X100, TIME

make display

still

c.

Set TRIGGERING

(1)

Connect signal generator (612A) to trigger input and to vertical input probe as infigure 5-5. Apply a 150-mv peak-to-peak, 1000-mc signal.

(2) Steady display should appear

justments 'of MODE, STABILITY and HIGH

FREQUENCY STABILITY controls.

Table 5-8. Time Scale Calibration Check

TIME SCALE

1

I.~SE~/CM

0.5

~SEC/CM

200

NSEC/CM

loo

NSEC/CM

50

NSEC/CM

20

NSEC/CM

io

NSEC/CM

to

HIGH FREQ.

MAGNIFIER

X50 X50 x10 x5 x5 Xl

x1

with

proper ad-

Cycles/lO cm

10

5 10 10

5 10

5

I

5-10

01255-1

Model 185B

Section V

Figure

5-6

R

503

HORIZONTAL

GAIN

\

R463

0401

0413

VERT.

c7

PEAKING

ADJ

AI

0

12

55 - 1

Figure 5-6.

Top

View,

Model

185B

5-11

Section V Model 185B Figures

5-7

and 5-8

53

CHANNEL

OUTPUT SCAN OUTPUT VSOI

0

J

202

TIME BASE

HIGH VOLTAGE

SUPPLY

R61

I

f

R446

R318

///;/yi

/

I

_.-

-

Figure

--

5-7.

Left

Side View, Model 185B

Y

*I/.

PR

-I

l5201

5401

\

8401

MOTOR

c.

/

LlOl

5-12 01255-1

SI02 PI02

(5102)

R309

VI01 VI02 V201 C408 C422 R436 C412 V401 R428 C402

Figure 5-8.

Right Side View, Model 1853

-1

\\\\\

L401

LIP- S -1025

Model

185B

Section

Figure

V

5-9

0402

0408

CR405 0405 CR406 A402

0

12 55 - 1

JlOl

SI01

R160

R115 R509 C215 C217 C2l9

Figure

5-9.

Bottom

View,

Si02

Model

S201

185B

Ri13

S203

S401

-

5-13/5

14

Model

1bSB

Schematic

Diagram

.ad

Waveform

Section

Note6

v

SCHRMATIC

”be

following

have specific

a.

All

tion

of

the

b.

Letters

first

wafer, B = rear aide, etc).

c.

(1)

number under waveforms opposite schematic.

(2)

d.

DC

e. Reristance

1.

“VF”

g.

DC

notes

rotary

CALIBRATOR

after

meam

@

*

meana optimum value

voltages taken

meana

voltages

apply

that apply

ndtches are

the

switch

that

a

with

is

in

ohms,

filtered

in

voltage.

trigger circuit are

SCANNING DENSITY

TIME

TIME SCALE MODE STABILITY TRIGGERING MGH FREQUENCY

STABILITY

generally

to

that

schematic

&own

full

AND

SYNC

wafer8

waveform

of

component electronic capacitance

.............

..............

SCALE

...............

..........

DIAORAM

to

all

#cbematic

clochrisa

PULSE rnsitch which

(Le.,

wa~

men

voltmeter

in

picofarad6 unlem otherwi6e

taken

with

MAGNIFIER

.........

...........

.........

only.

a6

SZOW)

at

See

mlecbd

having

controls

NOTRS

dhgram6.

viewed

identify htch wafers

that

waveform

at

from front panel,

point. The number

the

factory, average

10-megohm input resistance.

set

INTERNAL

.......

10

counterclockwise

catnterclockwise

Individual

is

shown

notes.

as

followa:

clockariee

X1

pSEC/CM

TRIGGER

NORMAL

full

noted.

rchematics

with

camterclochaiee.

(A

=

front side

in

center refers

value

ttLe

excep-

shown.

may

of

to

WAVRFORM

The following notes page. Waveforms are taken

a.

Switch

b.

Unless otherwise noted on the waveform page, where number, was taken

c.

External

“internal”

01255-1 5-15

settings are

the upper one

with

under

apply

to

all

waveforms unless specifically contradicted on the waveform

with

40-mc oscilloscope using a high-impedance probe.

as

follows:

SCANNING DENSITY

TIME SCALE MAGNIFIER

Time

Scale

TRIGGERING

CALIBRATOR

SYNC

waa

taken

TIME

SCALE

sync from viewing oecilloecope

the

waveform.

set

............

...........

VERNIER

...........

AND

PULSE.

to

.....

with

TIME

10

NSEC/CM.

NOTRS

INTERNAL

counterclockwise

full

counterclockwise

. .

full

counterclockwise

HIGHFREQ

fullcounterclockwise

SCALE

waa

two

set

to

used unless otherwise noted

waveforms are

200

NSEC/CM,

shown

and

the

lower one

by

over one

the

word

m

3

M

E

i

5

,.

,-

a

i

,*"

.

'.

292V

612Y3

C92M

022L1'

IC23

922Y

IEZ,

Model

185B

BRN/ORN

TO

R154-RI55

ASS

EM

B

LY

&

\A

TRtGGERING SWITCH

LOCATION

SI01

01255-1

ELK

;A

V102A

8

Figure

GHT

TO

Cll8

5-12.

TIME

Parts

LD-S-528

SCALE SWITCH

Location,

Switch

S202

Assemblies

1

I

Section

V

Figures 5-14 to 5-16

SCANNING SWITCH

h

S203

A501

ASS E

M

B

LY

LO CAT1 0 N

Model

185B

R2lS

C212 C214 C215 C217

. . . . ..

-

.

. . .

TO

R223

CR222

TIME SCALE

MAGNIFIER SWITCH

TIME SCALE SWITCH

S202

S201

VCI

NYT

5-18

Figure

5-16. Parts Location, Switch

Assemblies

01255-1

+

E

7--

I

J

v)

Ln

N

3

0

.

..

.

m

Lo

m

*

E

0

c

8

9;

N

Lo

W

I.

M

E

m

10

m

r(

4

-#

N

10

RED J40l

ID1

F40l 4ASB

2A

SB

(115V)

1230)

b+25OV

TO

TIME BASE

5

%

cd

9

1

REFERENCE

DESIGNATORS

C

401 - 422 CR401-413 DS401-405

F 401-406 L 401, 402

UNASSIGNED’

C 409.416-417 R

417-419.432-434.

447. 459-461

NOTES:

SEE GENERAL SCHEMATIC

2.

NOTES AT BEGINNING SCHEMATIC SECTION.

ON

TABLE

3.

GIVES PS RIPPLE AND

FACING PAGE

VOLTAGE LIMITS.

OF

0

TO

-29OOV AND

-2900V

a

2

P>

OS

i

+-3"

N

o

c

z

n

0

"

>

en

N

Lo

4

0

o

4

Lo

13

NX

00

IQN

urn

I

*

0=

rc)

I-

3

w

&I

&I.

I

Section

VI

Paragraphs 6-1 to 6-7

SECTION

REPLACEABLE PARTS

6-1.

INTRODUCTION.

6-2.

This

section contains information for ordering

replacement parts. Table 6-1

numerical order of their reference designators and

the

indicates

description and @ stock number of each

part, together with any applicable notes. Table 6-2

lists

parts in alpha-numerical order of their @ stock numbers and provides the following information on each part:

a.

Description of

the

part

below).

b.

Typical

code;

see

c.

Manufacturer's

manufacturer of

list

of manufacturers in appendix.

stock

d. Total quantityused in

e.

Recommended spare part quantity for complete

maintenance during one year of isolated service

(RS

column).

6-3.

Miscellaneous parts not indexed in table 6-1 are

listed

at

the end of table 6-2.

lists

(see

the

number.

the

instrument

parts in alpha-

list

of abbreviations

part in a five-digit

(TQ

column).

VI

6-4.

ORDERING INFORMATION.

6-5. To order a replacement part, address order inquiry either to your authorized Hewlett-Packard sales representative

CUSTOMER SERVICE Hewlett-Packard Company

395

Palo Alto, California

or,

in Western Europe, to

Hewlett-Packard S.A.

54-54bis Route des Acacias

Geneva, Switzerland

6-6.

Specify the following information for each part:

Model

a.

b.

C.

d.

6-7.

and complete Hewlett-Packard stock number. Circuit reference designator. Description.

To order give a complete description of the part andinclude function and location.

Page

a

part not

or

to

Mill

serial

listed

Road

number of instrument.

intables6-1 and 6-2,

its

or

A

=assembly

B

=

motor

C

=

capacitor

CR

=diode

DL

=

delay line

=

device signaling (lamp)

DS

E

=

misc electronic part

=

amperes

a bp

=

bandpass

bwo

=

backward wave

oscillator

c

=

carbon

=

ceramic

cer cmo = cabinet mount only coef

=

coefficient

=

common

com

=

compmition

comp

=

connection

conn

=

cathode-ray tube

crt

dep

=

deposited

EU

=

Tubes

or meeting Electronic Industries' Association standards will normally result in instrument operating

within specifications; tubes and transistors selected for best performance will

5

supplied if ordered

-

o

by 3 stock numbers.

transistors.

01255-1

be

REFERENCE DESIGNATORS

F =fuse

FL

=

filter

J

=

jack

K

=

relay

L

=

inductor

M

=

meter

MP

=

mechanical part T

=

electrolytic

elect encap= encapsulated

f

=farads

fxd =fixed

Ge

=

germanium

=

ground (ed)

grd h

=

henries

Hg

=

mercury

impg

=

impregnated

=

incandescent

incd ins = insulation (ed)

K

=

kilo

=

1000

lin = linear taper

log

=

logarithmic taper

m

=

milli=

M

=megohms

=

milliamperes

ma

p

=

micro

=

minat = miniature

=

metal film on glass

mfgl

mfr

=

10-6

manufacturer

P

Q

R RT

S

ABBREVIATIONS

mtg my

NC Ne NO NPO

nsr

=

plug

=

transistor

=

resistor

=

thermistor

=

switch

=

transformer

=

mounting

=

mylar

=

normaliy closed

=

neon

=

normally open

=

negative positive zero (zero temperature coefficient)

=

not separately replaceable

=

order

by

scription

=

peak

=

printed circuit board

=

picofarads

10-12

=

peak- to- peak

=

peak inverse voltage

=

position(s)

=

polystyrene

=

potentiometer

=

rectifier

de-

farads

=

V

=

vacuum bulb, photocell, etc.

W

=cable

=

socket

X

=

fuseholder

XF

XDS

=

lampholder

Z

=network

=

rotary

rot

=

root- mean- square

rms

=

rack mount only

rmo

6-b

=

slow-blow

Se

=

selenium

=

section(s)

sect

=

silicon

Si

=

silver

si1

SI

=

slide

td

=

time delay

=

titanium dioxide

Ti0

2

tog

=

toggle

to1

=

tolerance

=

trimmer

trim

=

traveling wave

twt

var = variable w/

=

with

W

=

watts

ww

=

wirewound

w,'

=

without

*

=

optimum value selected average value shown (part may

be

omitted)

tube,

at

factory,

neon

tube

6-

1

Section

Table

VI

6-1

Table

6-1. Reference Designation Index

XIoclcl

185B

Circuit

Reference

Al

A3

thru

AlOl

MOO

@

Stock

No.

185B-65B

I

185B-65A

185B-19

F

Deskription

Assy,

Assy, ELECTRONIC SWITCH etched

Not

Assy, TRIGGERING switch: includes,

VERTICAL AMPLIFIER etched

c1

thru

C22

2

CRl,

L1, 2

Q1

thru

R1

thru

Rs

R7

thru

C8

thru

C25 CR2

thru

L3

thru

assigned

Rl58,

c7 R14

C24 R21

e4

R3

FU1

C19

CR8 xv4.5

L5

FU59,

SlOl

thru

R25

R27

R56 R61

thNv3

xv1

R33

v4,5

Rl9

R23

thru

R29

thru

R58

thru

R64

thru

R55

xv3

circuit:

inclL

incluc

A102

A103

A104 A201

thru

A200

185B-65

185B-19C

N

Not

as

signed

Assy, SYNC etched

ClOl thru C109 L102 thru L104 C115 thru C117 L107 thru L114 C126 thru C130 QiOl thru Q107 C135 thru C138 C141

thru

C146

C151

thru

C159 R116 thru Rl21

cRl01,102 Rl26

CRl04 CRlll CRl16 Rl61 cRl20,122 Rl68 CFU24.125 Rl85 thru R195

CRl31 DLlOl v101,102 5102

Not asdgned

Assy, TIME SCALE MAGNIFIER switch: includes,

R212

R215

thru thru

thru

R220 s201

circuit:

CRl08 CRl14

CRl37

includes,

RlOl

thru

R107

Rlll

thru R114

thru

Rl36

thru

R147

R163 FU80

T103

R283

Rl40 FU51 thru Rl57

TlOl

R277

6-2

#

See

introduction to thte section

01255-1

Model

185B

Table

6-1.

Reference Designation Index (Cont'd)

Section

Table

VI

6-1

Circuit

Reference

A202

A203

A204

@

Stock

No.

186B-19B

185B-19A

185B-65E

Description

Assy, TIME SCALE

C118

thru

C122 c212

C203

thru

C206 C208 c210 s202

Assy, SCANNING

C240, R254

~SSY,

TIME BASE

c201,202 CR207

C207 L20 C209 Q201 c211 R201 C213 R214 C221

thru

C224 R222

thru

C226 C238,239 R240 C241,242 T201 CR201

C236 R23 8

thru

CR204 V201

switch: includes,

thru

R261,

etched

C214

R2

86

S203

circuit:

1

thru

thru thru

thru

Note

C219

includes,

CR222

Q203 R211

R236

R247 T204

A205

A301

A302

A401

tbN

thru

A300

A400

185B-65C

185B-65J

Not

as

signed

Assy, HV POWER SUPPLY

C301 C311

R301

Not

Amy, LV POWER SUPPLY

C403,404 Q414,415 C406,407 Q417 C411 C413 C417 C419

CR407 CR410 CR413 Q403,404 R469 Q406.407 V401

Q4lO

thru

C308

thru

C313

L301,302 V301,302

thru

R307

R309 R319

XV301,302

assigned

R403

thN

C415 R421,422

R424

thru

C421 R437

R439 R451 R465

thru

Q412 XV401

etched

thru thru

circuit:

€2317 €2324

includes

etched circuit: includes

thru

Q419

thru

R415

thru

R431

thru

R444

thru

R458

thru

R467

thru

R474

01255-1

#

See

introduction

to

this

section

6-3

Section Table

Circuit

Reference

VI

6-1

@

Table

stock

6-1.

No.

Reference Designation Index (Cont'd)

Description

Model

185B

-

Note

-

A40

2

A403

A404

A50

1

A502

A601

A60 2

thru

500

A600

185B-66K

1450-0045

185B-65D

185B-19E

185B-65P

Assy, RECTIFIER

CR401

Amy, SCALE LIGHT

D6402

Not assigned

Assy,

C501 V501

R501

R510

Not assigned

Assy, CALIBRATOR

includes,

L60 R60

Assy, TIME CALIBRATOR

C601 C607 CR601

L601,602 R604 L605 R612

thru

HORIZ.

thru

R512

6

3

thru

etched

CR404, CR408,409 CR411,412

lampholder: includes,

D84OS

AMPLIF'IER

R507

XV501

AND

R619

so1

T60

C606 L607 C612 Q60l

CR605 R601,602

circuit:

etched circuit: includes,

SYNC PULSE

1

etched

includes,

thru

circuit:

thru

thru thru

switch:

R624

includes,

Q603

R610 R618

a

B1 B40

c1,2 c3.4 C5,6 c7 C8

c9 c10

c11

c12 C13,14

C15 C16 C17

6-4

thru

1

B400

3140-00 20

0

140

-00

54

0

150

-00

15

0

140

-00

54

0

131-000

0

130

0

150-00 52

0

140

0

140 -010

0150-0052

0

140

0150 0150 0140-0054

-00

-0

11

-01

-00

3

1

7

6

1

16

52 24

Not assigned

Motor,

C:

C: C: C:

C: C: C: C: C:

C: C: C:

I)

See

ac

fxd, mica, fxd,

TiO2, 2.2

fxd, mica, var, mica, var,

cer,

fxd,

cer,

fxd, mica, fxd,

mica,

fxd,

cer,

fxd,

mica,

fxd,

cer,

fxd,

cer,

fxd,

mica,

introduction to

100

pf

*lo%,

pf

*lo%,

100

pf

*lo%,

50-380

8-50

dual tandem,

39

15

dual tandem,

39

dual tandem,

0.02

100

pf,

500

pf

*2%, 500

pf

*5%, 500

pf

*2%, 500

pf

+80% -20%. 600

pf

*lo%,

this

section

500 500

500

175

vdcw

0.05

500

vdcw vdcw

vdcw

ccf

vdcw vdcw

pf

vdcw

pf

vdcw

*20%, 400

i20%, 400

vdcw

-

01255-1

Model

185B

Table

6-1.

Reference Designation Index (Cont'd)

Scction

T&lc

VI

6-1

Circuit

Reference

C18 c19

c20,21 C22

thru

C25

thru

C26 c101,102

C103 C104 Cl08 c109 CllO

clll

C115 C116

thru

thN

C117

C118

C24

ClOO

C107

C114

@

Stock

No,

0

170

-00

3

8

0150 -0052

0150-0052 0 1 80

-00 5 8

0

150-0070

0

180-00 01 80-0076 01 80-00 89

0

1

0150-00

0

140 01 0140-0041 0

140

80

50

89

-00

7

84

-0

1

5

-0042

-0

1

5

6

2

8

C:

fxd, my,

C:

fxd,

cer,

Not assigned

C:

fxd,

cer,

C:

fxd,

elect,

Not assigned

C:

fxd,

cer,

C:

fxd,

elect,

C:

fxd,

elect,

C:

fxd,

elect,

C:

fxd,

elect,

C:

fxd,

cer,

Not

assigned

C:

fxd, mica,

C:

fxd,

TiO2, 4.7

C:

fxd,

mica,

C:

fxd, mica,

Description

0.22

pf

*lo%,

dual tandem,

50

pf

-10% +100%, 25

0.02

pf

*20%,

10

pf

-10%

20

pf,

25

10

pf

-10%+100%, 150

20

pf,

25

0.1

pf

+80%

1000

pf

i5%,

pf

*5%,

100

pf

&5%.

2676

pf

*l%,

200

0.05

500

+loo%,

vdcw

-20%, 50

300

500

vdcw

500

vdcw

pf

*20%, 400

pf

*20%, 400

vdcy

vdcw

150

vdcw

c119 c120 c121 c122

thru

C123

C126 C127

C128 C129 C130

C131

thru

C135 C136 C137 C138

C139,140 C141 C142

thru

C145

C146

C125

C134

C144

0140-0153 0140-0037 0140-0023 0140

-0081

0180-0059

0150-0050

0150-0073 0

150

-0096

0

140 -0041

0140-0078 0

150

-00

84

0

1

50

-0 0 37

0150-0012

0140 -0161 0150-0012 0150-0052 0140-0085

C:

fxd, mica,

C:

fxd,

mica,

C:

fxd,

mica,

C:

fxd,

mica,

Not assigned

C:

fxd,

elect,

C:

fxd,

cer,

C:

fxd,

cer,

C:

fxd,

cer,

C:

fxd,

mica,

Not assigned

C:

fxd,

mica,

C:

fxd,

cer,

C:

fxd,

cer,

C:

fxd,

cer,

Not

assigned

C:

hd,

mica,

C:

fxd,

cer,

C:

fxd,

cer,

C:

fxd,

mica,

1269

pf

*l%,

390

pf

is%,

180

pf

*lo%,

56

pf

*l%,

10

pf

-10%+100%, 25

1000

pf,

600

100

pf

aO%,

0.05

pf

+80% -20%,

100

pf

*5%,

2000

pf

*200

0.1

pf

+80% -20%, 50

100

pf

*l%,

0.01

pf

*2O%,

3932

pf

*I%,

0.01

pf

*20%%, 1000

dual tandem,

470

pf

*5%,

300

500

vdcw

500

pf

500

1000

300

0.05 500

vdcw

100

vdcw

pf

vdcw

*20%, 400

vdcw

01255-1

I

See

introduction

to

this

section

6-5

Section Table

Circuit

Reference

VI

6-1

8

Table

Stock

6-1.

No.

Reference Designation Index (Cont'd)

Description

Model

185B

7

Note

-

C147

thru

C151 C152 C153

dl84

C155

C156 C157

C158 C159

C160

thru

c201.202 C203 C204 C205

C206 C207 C208 c209 c210

C150

C20C

0150-0014 0150-0052

03.80

-00

76

01.60-86

0140 0150-0070

01

50 0150-0084 0140-0007

0180-0076

0

170-00

0170-0089

0170-0090

0170-0091 0131 0140-0189 0131-0003 0

140

-00

-000

-00

i

a

55

71

8

3

86

Not assigned

C:

fxd, cer,

C:

fxd, cer, dual tandem,

C:

fxd,

C:

ad,

C:

fxd,

C:

fxd, cer,

C:

fxd, cer,

C:

fxd, cer,

C:

fxd,

elect,

der,

mica,

0.005

20

pf,

0.01

150

0.02 400

pf

0.1

pf+80% -20%,

680

Not assigned

C:

fxd, elect,

C:

€xd,

C:

fxd, poly,

C:

fxd, poly,

C:

kd, poly,

C:

var, mica,

C:

fxd, mica,

C:

var, mica,

C:

fxd,

poly,

mica,

20

pf,

0.126

0.063

0.0252

0.01213 170-780

5825

170-780

2000

pf,

pf

pi

pf

500

25

*Zaqb,

*lo%,

62096,

&%,

*lo%,

25

pf pf

*l%,

pf

*2%,

pf

*5%,

vdcw

0.05

vdcw

500

vdcw

*l%,

*2%,

pf,

pf

load

500

vdcw

500

vdcw

500

50

vdcw

50

175

vdcw

300

175

vdcw

500

*20%,

vdaw

50

vdcw

400

vdcw

c211 c212 C213

C214 C215

C216 C217 C218 C219 c220

c221

c222 C223

C224

C225

C226 C227

6-6

0131-000 0140-0099 0

1

31

0140-010 7 0131-0004

0140-0036 0

131 0140-0006 0130-0001

0150-0052 018O-OO 89

01

80-00

0150-0084

01

80-00

0150-0052

-000

-00

3

1

04

58

59

C:

var,

C:

fxd, mica,

C:

var, mica,

C:

fixd, mica,

C:

var, mica,

C:

fxd,

C:

var, mica,

C:

fxd, mica,

C:

var, cer,

mica,

170-780

1000

50-380

507

14-150

110

14-150

82

pf

7-45

Not assigned

C:

fxd, cer, dual tandem,

C:

hd,

C:

fxd, elect,

C:

hd,

Not

assigned

C:

fxd,

C:

fxd,

#

See

introduction to

elect,

cer,

elect,

cer,

10

pf

5

pf

0.1

pf

10

pf

dual tandem,

this

pf,

175

pf

*l%,

pf,

175

pf

*2%,

pf

*5%,

*lo%,

pf,

500

175

500

175

500

vdcw

0.05

-10%+100%,

-10%

+100%,

+80%

-10%

section

-20%,

+100%,

0.05

500

vdcw

pf

*20%, 400

150

25

vdcw

50

vdcw

25

pf

*20%, 400

vdcw

01255-1

Model

Reference

185B

Circuit

Table

@J

Stock

6-1.

No.

Reference Designation Index (Cont'd)

-~

Description

~

Scction

Table

Note

VI

6-1

C228 C229 C230

C231 C232

C233,234

C235 C236

C237

C238

C239 C240 C241

C242 C243

thru

C301

C302

C303,304

C300

0140-0107 0

1 50

-00

14

0

150-0050

01

80

-00

76

0150-0012 0160-0050 0

150

-00

24

0170

-0 0

55

0140-000 2 0150-0012

0

180 -0097

0150-0052

0

1

50

-00

14

0150-0033 0160-0046 0150-0012

C:

fxd, mica,

C:

fxd, cer,

C:

fxd, cer,

C:

fxd, elect,

C:

hd,

C:

fxd,

C:

fxd, cer,

C:

fxd,

cer,

my,

507

0.005 1000

20

0.01

1000

0.02

0.1

pf,

pf

Not assigned

C:

fxd, mica,

C:

fxd,

cer,

C:

fxd, solid tantalum,

C:

fxd, cer, dual tandem,

C:

fxd,

cer,

10

pf

0.01

0.005

Not assigned

C:

fxd,

C:

fxd, paper,

C:

fkd, cer,

Ti02,

8.2

0.0033

0.1

pf

*2%, 500

pf,

500

pf,

600

25

vdcw

pf

*20%, 1000

pf,

600

pf

+80% -20%, 600

*20%, 200

*lo%,

pf

i20%,

47

pf,

500

pf

*lo%,

pf

*20%,

vdcw

500

vdcw

1000

pf

*lo%,

0.05

vdcw

500

*20%, 6000

1000

vdcw

35

pf

i20%, 400

vdcw

C305 C306 C307 C308 C309.310

C311 C312 C313 C314

thru

C401

C40 2 C403 C404 C405 C406

C407,408 C409 C410

C400

0160-0013

0

150-00 23

0140

-00

15

0150-0052

0

150-00 23 0160-0061 0150-0052

0180-0042

0180-001 2 0150-00 84 0170-00 18 0180-0030

0

150-00 84

0170-0018

0180-0077

C:

fxd, paper my,

C:

fxd,

cer,

2000

pf

C:

fkd, mica,

C:

fxd,

cer,

270

dual tandem,

Not assigned

C:

fxd,

cer,

2000

C:

fxd, paper,

8:

fxd, cer, dual tandem,

0.0015

Not assigned

C:

fxd, elect,

C:

fxd, elect, 2 sect,

C:

fxd,

cer,

C:

fxd, my,

C:

kd, elect, 2 sect,

C:

fxd, cer,

C:

fxd, my, 1 pf

0.1

1

0.1

120

pf

*5%, 200

pf

6%,

Not assigned

C:

fxd,

elect,

4500

0.1

pf

*lo%,

*20%, 1000

pf

*lo%,

pf

*20%,

pf,

350

+80% -20%, 50

500

0.05

1000

pf

*20%, 5000

0.05

vdcw

20

pf / sect,

vdcw

120x40

+80% -20%, 50

200

pf,

35

pf,

vdcw

400

vdcw

vdcw vdcw pf

i20%, 400

vdcw

pf

*20%, 400

450

vdcw

450

vdcw

01255-1

#

See

introduction to

this

section

6-7

Section Table

VI

6-1

Table

6-1.

Reference Designation Index (Cont'd)

Model

185B

Circuit

Reference

C411 C412

C413,414 C415

C416 (2417 C418

(2419 C420 C421 C422 C423

thru

C501 C502

thru

C601 C602 C603

C500

C600

@

Stock

No,

0

150-0

0

84

01

80-00 56

01

50-00

0180-0059

84

0150-0052

0180-0042

0150-0052

01

80-0059 0150-0012 0

180-0004

01

50

-0050

0

150-00

0140-0 213 0180-0045

84

C:

fxd, cer,

C:

fxd, elect,

C:

fxd, cer,

C:

fxd,

elect,

0.1

1000

0.1

10

pf

Not assigned

C:

fxd,

cer,

dual

tandem,

C:

fxd, elect,

C:

fxd, cer, dual tandem,

C:

fxd, elect,

C:

fxd,

cer,

C:

fxd, elect,

120

10

0.01 20

pf

Not assigned

C:

fxd, cer,

1000

Not assigned

C:

fxd, cer,

C:

fxd, mica,

C:

fxd, elect,

0.1 2000 20

pf

pf,

Description

+80%

pf,

+80%

pf,

pf

pf,

-20%.

50

vdcw

-20%

-1O%+lOO%, 25

350

vdcw

-10%

ilOO%,

*20%, 1000

-10%+100%, 150

600

vdcw

+80% -20%, 50

pf

*l%,

25

vdcw

0.05

300

50

pf

vdcw

120%

*20%, 400

25

vdcw

400

vdcw

C604 C605 C606 C607 C608

C609 C610 C611,612 C613

CRl

thru

cR8

cR9

thru

CRlOC

cR101,102

CRl03 ClU04

ClU05 Cm06 CRl07,108 cR109,110 ClUll

0150-00 S2

01

50-00 84

0180-0059

0150

-00

52

0150-00 84

0150-0029 0130-0019 0150-00 78 0150-0012

1910-0016

1902-0031

1910-0016

G29E-46 G29E-86 1901-00 27

1903-0002

C:

fxd, cer, dual tandem,

C:

fxd,

cer,

0.1

pf+80% -2096, 50

C:

fxd, elect,

C:

fxd, cer, dual tandem,

C:

fxd, cer,

C:

fxd,

TiO2, 1 pf

C:

var, cer,

C:

fxd, cer,

C:

fxd, cer,

Diode,

Ge

10

0.1

4-30

56

0.01

pf

Not assigned Diode, avalanche

Not assigned

Diode,

Ge

Diode Diode

Diode,

Si

Not assigned

Diode,

Si

-10%

+80%

*1%,

pf,

aO%,

-20%, 50

500

*20%,

0.05

pf

&20%, 400

+100%, 25

0.05

pf

&20qb,

vdcw

1000

vdcw

1000

vdcw

400

vdcw

6-8

#

See

introduction to

We

section

0

1255-1

Model

185B

Table

6-1.

Reference Designation

Index

(Cont'd)

Section

Table

VI

6-1

Circuit

Reference

-

Cml2 CRl15 CRl16 CRl.17

clu20

cRl21.122

CRl23 CR124,125 CRl26 CRl31,132

CRl33 CRl36.137 C138 cR201 CR202.203

C CR205,206 CR207.208 CR209 CR210

thru

R204

114

119

130

135

200

@

Stock

~ ~~

1901-00 27

1912-0005

19124004

1801-0027

G29L-78

G29M-8

1910-00 16 G29 L-7

G29L-78 G29M-9

1910-0016

191

G29M-8

No.

2-0002

8

Diode,

Not

Diode,

Not

Diode,

Rot

Si

assigned

Ge:

tunnel

assigned

Ge

Si

assigned

Diode

Not

assigned

Diode

Diode,

Ge

Diode

Not

assigned Diode Diode

Diode,

Not

Diode,

9

assigned

Ge

Diode, tunnel Diode

De

ecription

Note

cR211 cR212 CR213.214 CR215

CR216

CR217 CR218 CR219 cR220 cR221

cR222 CR223 CR401 CR405.406 CR407

CR408,409

01255-1

thru

400 404

10-00

1

3

6

2

19 G-29M-8

G29 E-12 G29M-9

G29M-8

G29M-9 1910-0016 G-29E-46 G31A-82L G31A-7H

1910-0016

1901-0029 190 1-00 G-29A-74

1901-00 26

Diode,

Ge

Diode Diode Diode

Diode

Diode Diode,

Ge

Diode

Diode, Zener

Diode,

Not

Diode, Diode,

Ge

assigned

Si

Si:

1N3209

Diode, Zener

Diode,

#

See introduction

Si

to

this

section

6-9

Section

Table 6-1

VI

Circuit

Reference

@

Table

Stock

6-1.

No.

Reference

Designation Index (Cont'd)

Deecription

Model 185B

-

Note

CR410 CR411,412 CR413

CR414 CR601.602

C

CR604 CR605

DL1 DLlOl

Fl

F401

F40 2 F403 F404 F40 5 F406

R60 3

thN

thru

thm

F400

600

100

G29A-74 1901-0029 G31G7H

1910-0016

G29L-49 G29 5-38 629 5-48

9190-0003

1450-0039 2140-0009

2110-0014 2110-000

2110-0004 2110 -001 2 2110

-0030

2110-0004 2110-0012

6

Diode, Zener Diode, Diode, Zener Not assigned

Diode, Diode Diode Diode

Not assigned Line, delay: 1000

Not assigned tamp, neon: NE2H Lamp, indicating: 0.15 amp

Not assigned

Fuse, cartridge: Fuse, cartridge: 2 amp,s-b (for 230

hse,

Fuse, cartridge: Fuse: 5 amp, s-b

Fuse,

Si

Ge

ohms,

4

amp, s-b (for 115 v operation)

cartridge: 1/4 amp, 250

1/2

cartridge: 1/4 amp, 250 cartridge: 1/2 amp, 250

1

microsecond

amp, 250

v

v v

v

operation)

a

J1 J2,3

thru

54

JlOl

5102 5103

5201,202

6-10

JlOO

thN

J200

-00

1251

AC-1OC AC-1OD AC-64D AC-54E

1250-0102 1250-00 83

AC-1OC AC-1OD AC-54D

54

Connector: female Channel

Not assigned Connector, body Connector, Not assigned

Output time base scan (J202), input

4

See

A

output (J2), channel B output (53): includf Binding post: black Bindingpost: red Insulator, binding Insulator,

(5201) Binding post: black Bindingpost: red Insulator, binding post: black,

introduction

binding

rf:

52

:

includes,

or. bm

to

ohms,

this

post:

type

DO&

section

black, 1 hole black, 2 hole

UGlO94/U

black.

external

1

hole

2 hole

scan

01255-1

Model 185B

Circuit

Reference

Table 6-1. Reference Designation Index (Cont'd)

@

Stock

No.

Deckription

Section

Table 6-1

VI

-

Note

5203

thru

540

1

5402

5601,602

5603

thru

L1,2

thru

L3 L6

thru

LlOl L102.103

L104 L105,106 L107,108 L107 L114

L201 L202

L115

thm

thru

L301

L302

5400

5600

LlOO

L113

L200

L300

12514130

1250-0102 1250-0118

9140-0029 9140-00 20

-00

11

37

9140-0 9170-0029

9140-0107

9140-0029 9170-0029 9170-0016

9140-0019

9140 9140-0019

6

Not assigned

rf:

5

rf:

ph

bead

ph

bead

mh

female

BNC

1.1

ph

-

2.0

ph

2OOph

ph

Connector, Not assigned Connector, body:

Connector,

Inductor: 100 Inductor: 400 Not assigned Inductor:

Core,

Inductor: fxd, 27 Not assigned Inductor. 100 Core,

Shielding bead: manganese

Not assigned Inductor: fxd, Not assigned Inductor: Inductor: fxd, 200

V~F,

ferrite

ph

zinc

ferroxide

L303

LAO1

IA02

L403 L601,602

L603,604 L60 5 LG06 L607

P1

thN

P102 P103 P401

Q1

thru

Q5

thru

QlOl

01255-1

thru

PI01

thru

84

QlOO

thm

MOO

L600

P400

Q103

9110-0031 G60A

9170

-00

29

185B-60G 9140-0028 9140-0027

1250-0052

8120-0015

1850-0037

1851-00 21

Not assigned

Reactor, Inductor, alignment Not assigned Core, ferrite bead

Not assigned Inductor: fxd, 0.16 Inductor: 2.2 Inductor:

Not assigned Connector, plug Not assigned Cord, power

Transistor: 2N274 Not assigned Transistor: 2N377A

#

See

filter

choke: 6

ph

35

ph

introduction

to

this

mh

ph

section

6-11

Section

Table 6-1

VI

Circuit

Reference

Table 6-1.

Reference Designation Index (Cont'd)

De

scription

Model 185B

-

Note

Ql04,105 Q106 Q107

Ql08

thru

Q20l

Q20

2

Q203

Q204 Q205.206 Q207

Q20

8 Q209 Q210

Q2ll

thru

Q401.402

Q204

Q4OC

1850-0066 1854-0004 1850-0067

1860-0012

1850-0052

1851-0017

1854-0004 1850-0051

1850-0067 1851-0011 1850-0052

-00

56

62

1850

1850 1850-00 56 1851-0017 1850-0062 1850-00 21

Transistor: 2N700 Transistor: 2N743 Transistor: 2Nl495

Not

assigned

Transistor:

@

type 1850-0010, color coded blue)

Transistor: 2N598 Transistor: 2Nl304

Not

assigned Transistor: 2N743 Transistor: 2N1500

Transistor: 2N1495 Transistor: 2N440 Transistor: 2N598

Not

assigned

Transistor: 2Nl159

Transistor: Transistor: 2N1159 Transistor: 2N1304 Transistor: special 2N404 Transistor: 2N441

2Nl23

special

(specially

2N404

selected

from

Q409 Q410

Q413 Q414,415

QQ16 Q417

Q420 Q601

QGo2 Q603

m,

2

R3

R4

R5

R6

6-12

thru

Q41:

thru

Q4lS

thru

Q600

1850-00 38

1850-00 62 1850-00 38 1850-0062 1850-0056

1850-0062

1850-0073 1851-0017 1850-0018

0687-4711 0765-0005 2100-0006 0765-0005 2100-0 231

Transistor: 2N301 Transistor: special 2N404 Transistor: 2N301 Transistor: special 2N404

Transistor: 2N1159

Transistor: 2N404

Not

assigned Transistor: 2Nl204 Transistor: 2N1304 Transistor: 2N384

R

fxd, comp, 470 ohms

R:

fxd, mfgl, 8.2K

R:

var,

ww,

5K

R:

hd, mfgl, 8.2K ohms

R:

var,

comp,

#

&e

introduction

ohms

lin, 2

to

this

ohms

*lo%,

sect,

section

*lo%,

&lo%,

1/2

w

2

w

3

w

*lo

%,

2

w

100 ohms i20%,

1/2

w

01255-1

Model

Reference

185B

Circuit

Table

@

Stock

6-1.

No,

Reference Designation Index (Cont'd)

Description

Section

Table

-

Note

VI

6-1

R7

R8

R!3,10

Rl1

ft112,13

Rl4.16

R16 R17,18 Rl9 R20

R21

R22 R23 R24

R25

R26 R27 R28.29

R30

thru

R33

R32

0687-1041 0686-2435 07 27-0 0764-0005

0687-6601

0764-0006 0760-0008 0765-0002 06904731

0764-0006 0686-2435 0687-1041 2100-0231 0765-0005

2100-0006 0765-0005 0687-4711

0690-2721

131

R

fxd, comp,

R

fxd, comp,

R

fxd, dep c,

R

fxd, mfgl,

Not

assigned

R

bcd,

oomp,

R

fxd, mfgl,

R

fxd, mfgl,

R

fxd, metallic oxide,

R

fxd, comp,

R

fxd, mfgl,

R

fxd, comp,

R

fxd, comp,

R

var,

comp

R

fxd, mfgl,

R

var,

ww,

R

fxd,

mfgl,

R

fxd, comp,

Not

assigned

R

fxd, comp,

lOOK

24K

3920

10K

56

18K

470

47K

18K

24K

lOOK

lin, 2 sect,

8.2K

5K~hms

8.2K 470

2.7K

ohms

*lo%,

ohms

*lo%,

*5%,

*l%,

i5%,

2

&lo%,

i5%,

2

i5%,

1

6.8K

ohms

&lo%,

&5%,

2

i5%, 1/2

*lo%,

100

*lo%,

3

*lo%,

1/2

w

1/2

w

1

w

1/2

ohms

2

w

2

w

1/2

1

w

*lo%,

w

*20%,

w

2

w

1/2.w

R34

R35

R36 R37 R38

R39 R40 R41 R42 R43

R44 R45

R46 R47 R48

R49

€250

01255-1

0727-0218 0687-5601 0727-0202 0686-3325 0687-2211

0686-3325

0690-2721 0727-0 21 0687-5601 0727-020 2

0693-4721 0687-5601 0687-4731

0

693-4721

0687-1021

0687-1031 0687-8211

8

R

fxd, dep

R

fxd, comp,

R

fxd, dep

R

fxd, comp,

R

fxd,

R

fxd, comp,

R

fxd, comp,

R

fxd, dep c,

R

fxd,

R

lkd, dep

R

fxd, comp,

R

fxd, comp,

R

fxd,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

hd, comp,

Y

See

introduction to

c,

220

ohms

comp,

c,

comp,

180K

56

ohms

83K

3.3K

*lo%,

3.3K

2.7K

180K

56

ohms

83K

4.7K 56

ohms

47K

4.7K 1K

ohm

10K 820

this

ohms

*lo%,

ohms

1/2

ohms

*lo%,

ohms

*lo%,

ohms

*lo%,

ohms

*lo%,

ohms

*lo%,

section

*1%,

1/2

il%,

1/2

*5%,

w

*5%,

*lo%,

il%,

1/2

*l%,

1/2

*lo%,

1/2

*lo%,

1/2

1

1/2

2

1/2

2

w

1/2

w

6-13

Section

Table

R51 R52 R53 R54

R55

R36

R59,60

R61 RG5 mol, 102

Rl03

Rl04

R105

Rl06 R107

VI

6-1

Circuit

Reference

thru

thm

RS8

R64

RlOO

Table

@

Stock

0687-5601 0693-39 21 0690-2211 0687-4731 0687-1031

0

690

0687-1051

06874711

0687-1011

0

690-1 231 0687-5601 0670-1531 0693-3901

6-1.

No.

470

1

Reference Designation Index

Description

R:

fxd,

comp,

R:

fxd,

comp,

R:

fxd, comp,

R:

fxd,

comp,

R:

fxd, comp,

R.

fkd,

aomp,

Not assigned

Fk

fxd, comp,

Not

assigned

R

fxd, comp,

Fk

fxd, comp,

R:

fxg,

comp,

R

fkd, comp,

R

fxd, comp,

R

fxd, comp,

56

ohms

309K 220

ohms

47K

ohms

10K

ohms

47

ohma

1M

*lo%,

470

ohms

100

ohms

12K

ohms

56

ohms

15K

ohms

39

ohms

*lo%,

ohms

*lo%,

do%,

1/2

*lo%,

*lo%, 1/2

*lo%,

(Cont'd)

1/2

w

2

w

1

w

1/2

.1/2

1

w

1/2

w

1/2

1

w

1

w

1

w

Model

185B

-

Note

Rl08

Rlll Rl12 Rl13 Rl14

Rl15

Rl16 Rl17

Rl18

Rl19

R120

Rl21

R122 Rl26

Rl27 R128

Rl29 Rl30 Rl31 Rl32 Rl33

thru

RllO

Rl25

0767-0006 0758-00 20 0687-5601 0758-0022

2100-030 5

0758-0021 0758-0018 0687-5601 0687-8211 0686-4345

0687-7525

0

690 -1 831 0687-5601 06 87-1031

0687-5601 0727-0109

0

727

-0

352

0727-0128

0727-0140

Not

assigned

R

fxd,

mfgl,

R

fxd,

mfgl,

R

fxd, comp,

R

fxd,

mfgl,

R

var,

comp,

20

C

log,

R

fxd,

mfgl,

R.

fxd,

mfgl,

R:

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

Not assigned

R

hd, comp,

R

fxd,

comp,

k

fxd, comp,

R

fxd, comp,

R

fxd, dep

R:

fxd, dep

R

fxd, dep c,

R

fxd, dep

605K 22K

56

82K

2

150K

51K

15K

56 820 430K

7.5K

18K 56 10K

56

c,

1470

c,

1.2K

3.60K

c,

6K

ohms

sect

(includes

ohms

*5?&

*5%, 1/2

*lo%, 1/2

*5%, 1/2

*20%, 1-1/4 *5%, 1/2 *5%, 1/2

*lo%,

*lo%, 1/2

*lo%,

*l%,

3

W

w

m60)

w

1/2

w

*5%, 1/2

*5%, 1

*l%,

*1/2%, 1/2

il%,

1

1/2

w

1/2

w

6-14

9

See

introduction

to

this

eection

01255-1

I

Model

Reference

185B

Circuit

$3

Stock

Table

No.

6-1.

Reference Designation Index (Cont'd)

De

scription

Section

Table

-

Note

VI

6-1

Rl34 Rl35 Rl36 Rl37

R140

FU41 Rl42 R143

xu44

R145

R146 Rl47 Rl48

R151

R152

R153

m54

R155

XU56 m57

thN

thru

R15(

0687-2241 0687-1801 0687-4711

0687-5611

0687-1221

0

6 87-1041

0687-1221

0686-2235 0686-2745

0687-8211 0687-1041

0683-2245 0727-0023

0

6 83-30 0687-3931 0727-009 8 0727-0012

2100-0154

15

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

Not assigned

R:

fxd,

comp,

R:

fxd,

comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

Not assigned

R

fxd, comp,

R

fxd,

dep

R

fxd, comp,

R

fxd, comp,

R

fxd, dep c,

R

fxd, dep c,

R

var, comp,

c,

220K 18

ohms

470

560

1.2K lOOK

1.2K 22K 270K

820

lOOK

220K

50

ohms

300 39K 945 20

ohms

lin,

ohms

ohms ohms

ohms

ohms ohms

ohms

1K

ohms

*lo%,

1/2

*lo%,

*lo%, *lo%,

*5%,

*lo%,

i5%,

*l%,

1/2

*5%,

1/4

*lo%,

*1%,

1/2

il%,

1/2

*30%, 3/10

1/2

1/2w

1/2 1/2 1/2

1/2

1/4

w

1/2

w

R158

R159 R160

Rl61 Rl62

R163 R164

R168.169 Rl70

Rl71

Rl72 Rl.73 R174 R175

R176

01255-1

thN

Rl61

0757-0062 0727-0027

-0

30

2100

0686-2015 0687-1071

0727-0027

0727-0035 0686-1025 0687-1821

0686-20 25 06 86-10 25 0686-1525 0686-9115 0727-0354

5

R

fxd,

mfgl,

R

fxd, dep c,

R

var, comp,

10

CC

log,

R

fxd,

comp,

R

fxd, comp,

R

fxd, dep

Not assigned

R

fxd, dep

R

fxd,

comp,

R

bed,

comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, dep

I

See

introduction

510

ohms

53.3

2

sect

1K

ohm

200 100

c,

53.3

c,

68.4

1K

ohm

1.8K

2K

ohms

1K

ohm

1.5K

910

c,

37.95K *1/2%, 1/2

to

this

ohms

(includes

aO%,

ohms ohms

ohms

*5%, 1/2

ohms

*5%,

ohms

section

*2%, 1/2

il%,

*5%,

*lo%,

*l%,

*1/2%, 1/2

*lo%,

f5%,

*5%,

1-49

1/2

*5%,

1/2

Rl15),

1/2

w

1/2

w

1/2

w

6-15

Section Table

VI

6-1

Table

6-1.

Reference Designation Index (Cont'd)

Model

185B

Circuit

Reference

Rl77

Rl78

Rl79 Rl80

Rl81

Rl85

Rl86 R187 Rl88

Rl89

Rl90 Rl91 Rl92 Rl93 Rl94

Rl95

Rl96

R201

R202 R203

thru

R184

R200

@

Stock

No,

0686-3025

0

6 86-47 0687-1021 0687-8211

0687-1001

0687-5611 0687-1001

0

684-10 31 0687-8211

0

687

07

67 -0004 0687-1211 0687-8211 0687-1011

0

7

64-0

0767-0009 0

6 87-6 821

0

727-01 20

-10

00

15

21

2

R

fxd, comp,

R

fxd, comp,

R

fxd,

R:

fxd,

Not

assigned

R

bd,

R

fxd,

R

fxd, comp,

R:

fxd, comp,

R:

fxd, comp,

R

fxd, comp,

R:

fxd, mfgl,

R

fxd, comp,

R

fxd,

R:

fxd, comp,

R

fxd,

Not

assigned

R:

fxd, mfgl,

R:

fxd, comp,

R:

fxd, dep c,

comp, comp,

eomp,

comp,

mfgl,

3K

ohms

470

1K

ohm

820

10

ohms

560

10

ohms

10K

820

1K

ohms

5K

ohms

120

820

100

7.5K

12K

6.8K

2.25K

Description

*5%,

ohms

*lo%,

ohms

*105%,

ohms

*lo%,

ohms

*lo%,

*5%,

ohms

ohms ohms

ohms

*5%,

ohms

1/2

w

*5%, 1/2

1/2

w

*lo%,

*lo%, *lo%, *lo%,

*5%,

1/2

3

w

1/2

1/;1

1/2

2

3

*lo%,

*I%,

1/4

w

1/2 1/2

Note

W

w

w w

w

R204

R20

5

R20

6

R20

7

R20

8

R209

R210

R211

R212

R213

R214

R215

R216

R217

R218

R!219,220

6-16

0687-2241 0687-1031 0687-5611 0690-2231 0687-1021

0

687-1011 0763-0006 0

6 8 6-9 2100 2100-0223

0

727-0060 0727-0090 0727-0047 0687-5601 0686-3305

0686-1005

-0

10

5

293

R

fxd, c6mp,

R:

fxd,

comp,

R:

fxd, comp,

R

fxd, comp,

R:

fxd, comp,

R

fxd, comp,

R

fxd, mfgl,

R:

fxd, comp,

R

var,

ww,

R:

var, comp, lin,

R

fxd,

dep c,

R

fxd, dep c,

R:

fxd,

dep c,

R

fxd,

comp,

R

fxd, comp,

R

fxd,

comp,

#

See

introduction

220K 10K 560

22K 1K

100

27K

91

lin,

225

750

144

56 33

10

to

ohms

1K

600

ohms ohms

ohms ohms ohms

ohms

this

ohms

*lo%,

*20%, 4

*5%,

ohms

*lo%,

*5%,

section

*lo%,

*lO%,

1/2

*5%,

*lo%,

*l%,

1/2 1/2

1/2

1/2w

1/2

1

w

1/2

w

3

1/2 1/2

1/2

w w

w

1/2

w

01255-1

Model

185B

Table

6-1.

Reference Designation Index (Cont'd)

Section

Table

VI

6-1

Circuit

Reference

R221

thN

R222 FU26.227

-28 R229

RlwO

R231

€4232

R233

R234

5

R23

R236 R237 R23

8

R239

RZ40

R941

R242

R243

R244.245

R226

@

Stock

No,

0687-1031 0687-1001 0687-5601 0699-0002 0687-5601

0

BBO-169

0687-1521 0687-2711 0687-8211 0687-1021

0699-0002 2100-0227

0687-1021

0727-0043

0687-1001 0687-5601 0687-4701 0687-1021

Description

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

fxcl,

1

R

Not assigned

R

Not assigned

R:

R.

R R R

oomp,

fxd, comp, fxd, comp, fxd, comp, fxd, comp,

kd, comp,

var,

ww,

fxd, comp,

&d, dep c, fxd, comp,

fxd, comp, fxd, comp, fxd, comp,

10K 10 56

6.8 56

16K

1.5K 270

820

1K

6-8

lin,

1K

100 10 56

47

1K

ohms ohms ohms

ohms

ohms ohms ohms

ohm

ohms

20

ohms

ohm

ohms

ohms ohms ohms

ohm

*lo%,

1/2

*lo%,

1/2

*l%,

*lo%,

1/2

1/2 1/2 1/2

1/2

1

1/2

1/2 1/2 1/2 1/2

w

1/2

w

1

w

w w

w

Note

R246

R247

R248

R.249

R250

R2S1 R252 R253 R254

R255

-56

R257 R258 R259 R260

01255-1

0687-8211

0687-1031

0687-1021 0687-1011

0

7

60

-000

0727-0169 0727 -0167 0687-2241 2100-0280

0687-1821 0686-3025 06 87-1031 0686-8255 0686-4735

9

R

fxd, comp,

R

fxd, comp,

Net

assigned

R

fxd, comp,

R

fxd, comp,

Fk

fxd, mfgl,

R

fxd, dep c,

R

fxd, dep c,

R

fxd, comp,

R

var, comp, lin, dual ganged,

1st

sect:

2nd

sect:

R:

kd, comp,

R

fxd, comp,

R

fxd, comp,

R

kd, comp,

R

&d, comp,

#

See

introduction to

820

ohms

10K

ohms

1K

ohm

*lo%,

100

ohms

lOOK

ohms

15.5K

13.7K 220K

50K

10

c log,

1.8K

3K

10K

8.2M *5%, 1/2

47K

ohms

tNe

ohms ohms

*20%,

30K

section

*lo%,

*2%,

1/2

1

*lo%,

*l%,

*lo%,

1/3

ohms

*lo%,

*5%, 1/2

*lo%,

6596,

1/2

w

1/2

w

1/2

w

1/2

w

1/2

w

*lo%,

1/2

w

1/3

w

6-17

Section

Table

VI

6-1

Table

6-1.

Reference Designation Index (Cont'd)

Model

185B

Circuit

Reference

R261 R262 R263 R264

mi36

R266 R267 R268 R269 R270

R271 R27 2 R273,274 R275 R276 R277 R278

@

Stock

No.

0 7 27-0 14 0687-5601 0687-1041 0687-2741

8

7

88-000 7

0690-1231 0 7 5

8

0687-1041

21

00 -0

0765-0008

0

7

5

8

0

7

67

0727-0148

0727-0 15 8

07

27-0140

-00

1

8 2

-00

19

-0009

8

6

R

fxd, dep c,

R

fxcl,

comp,

R

fxd, comp,

R

fxd, comp,

fi:

ixd,

mfgl,

R

fxd,

comp,

R

fxd, mfgl,

Not

assigned

R

fxd, comp,

R

var, comp, lin,

R

fxd, mfgl,

R

kd,

mfgl,

Not

assigned

R

fxd,

mfgl,

R

fxd, dep c,

R

fxd, dep c,

R

fxd, dep c,

7,842 56

ohms

lOOK 270K

1SK

12K

300

lOOK

68K

18K

12K

7,842

10.1K 6K

Description

ohms

*lo%,

ohms ohms

ahma

ohms

3.3K

ohma

ohms

f1%,

1/2

*lo%,

do%,

*lo%,

*5%,

2

1/2

*lo%,

ohme

*lo%,

*5%,

*l%,

*lo%,

2

1/2

3

*l%,

1/2

w

1

1/2

w

1/2

w

1/3

w

Note

w

R279 R2 80 R281 R282,283 R2 84

R285

13286

R287

thru

R301

R302

R303 11304

12305

R306

R307

R308 11309

R310

R311

R312

WOO

07

27

-0

11

07

27

-0

100

0727-00ai

0

727

-00

54

0687-5601

2100-0053 2100-0230

0699-001 2 06 87-8241

0687-1051 0690-2741 0699-0011 2100

-009

0836-0002

210

0

-0

10

0687-6841

0687-2731

0687-1241

2100

-0095

5

6

R

fxd, dep c,

R

fxd, dep c,

R.

kd,

dep

R

fxd, dep c,

R

fxd, comp,

R

var,

ww,

R

var, comp,

Not

assigned

R

€xd, comp,

R

fxd; comp,

R

fxd, comp,

R

fxd, comp,

R

fxd, comp,

R

var, comp,

R

fxd, dep c,

R

var,

coiiip,

R

&d, comp,

R

fxd,

comp,

R

fxd, comp,

R

var, comp, lin,

c,

10K

2K

ohms

1K

ohm

600

ohms

200

ohms

56

ohms

65K

ohms

27K

ohms

820K

1M 270K

1.8M

20M

680K 27K 120K

ohms

*lo%,

ohms

*l%,

lin,

1M *30%, 1/4

*lo%,

3.5M

*30%,

ohms

lOOK

*l%,

1/2

*l%,

*lo%,

*20%, 1/4

*lo%,

1/2

*lo%,

1/2

1

w

1/2

*lo%,

ohms

1/2

500

w

1/2

*30%,

w

1/2

1

w

1/2

w

v,

w

1/4

2

w

6-1

8

#

See

introduction

to

this

section

01255-1

Model

Reference

R313

R314 R315 R316

R317

R318 R319 R320 R321 R322

R323

R3

24 R425 R401 R40 2

185B

Circuit

thru

R400

Table

@I

Stock

No.

~~

0687-1541 0687-1021 0687-4731 0687-1021

0687-1041

2100-0009

0687-3931

2100-0096 0836-0003

0687-2241

0687-4731 0687-1551

0687-3331 0687-1041

6-1.

Reference Designation Index (Cont'd)

Description

R

fxd,

R

fxd,

R

fxd,

R

fxd,

R

fkd,

R

var,

R

fxd,

R

var,

R

fxd, dep

R

fxd,

R

fxd,

R

fxd,

Not

assigned

R

fxd,

R

fxd,

comp, comp, comp, comp,

comp,

gomp,

comp,

comp, comp,

150K

1K

47K

1Kohm

lOOK

25K

39K

lin,

c,

29M

220K

47K

1.5M

33K

lOOK

ohms

ohm

&lo%,

ohms

*lo%,

ohms

1M

*lo%,

ohms

*lo%,

ohms

*lo%,

1/2

*lo%,

1/2

*lo%,

*20%,

*lo%,

GO%,

1

w

*lo%,

1/2

*lo%,

1/2

1/3

1/2

1/4

1/2

w

1/2

w

1/2

w

1/2

w

Section

Table

VI

6-1

-

Note

R403

R404 R405 R406 R407

8

R40 R409 R410 R411 R412

R413 R414 R415 R416 R417

thru

R420 R421,422 R423 R4 24 R425

R419

0690-2701 0768-0001

0690-2701

0768-0001

0

81 3-00 2 8

0693-1031 0687-2211 0 76 7

-00

10

0727-0074 0767-0008

0687-1011 0767-0010 0767-0017 2 100

-000

0687-1041 0812-0016 0816-0003 0690-2231 0687-8211

6

R

fxd,

R

fxd, mfgl,

R

fxd,

R

fxd, mfgl,

R

fxd,

R

fxd,

R:

fxd,

R

fxd, mfgl,

R

fxd, dep

R:

fxd, mfgl,

R

fxd,

R

fxd, mfgl,

R

fkd, mfgl,

R

var,

Not

assigned

R

fkd,

R

fxd,

R

fxd,

R:

fxd,

R:

fxd,

comp,

ww,

comp, comp,

c,

comp,

ww,

comp,

ww, ww,

comp, comp,

1K

1

ohm

15K

10K

15K 17K

5K

25 500

27

ohms

ohm

27

ohms

ohm

10K 220

436

100

ohms

lOOK

ohms

22K 820

*lo%,

ohms

ohms ohms ohms

*lo%,

*5%,

*5%, 3

*lo%,

ohms

*3%,

*lo%,

ohms

1

w

3

w

1

w

3

w

1

w

*lo%,

*1/2%, 1/2

*lo%,

5

3

w

10

3

w

2

1/2

w

1/2

w

1/2

w

1

1/2

w

R426 R427

01255-1

0687-1 821 0690-2231

Fk

R

#

See

fxd, fxd,

comp, comp,

introduction

1.8K

ohms

22K

ohms

to

thia section

*lo%,

1/2

1

w

6-19

Section

Table

Circuit

Reference

R428 R4 29 R430 R431

R432

VI

6-1

thru

R43~

Table

63

Stock

0687 -10 0761-0004 2100-0282 0761-0004

6-1.

No.

11

Reference Designation Index (Cont'd)

Description

R

fxd,

R

fxd, mfgl,

R:

var,

R

fxd, mfgl,

comp,

ww,

100

20K

lin,

20.K

ohms

2K

ohms

*5%,

ohms

*5%,

*lo%,

1/2

1

w

*20%, 1-1/2

1

w

Not assigned

w

Model

185B

-

Note

R435 R436 R437 R43 8 R439

R440 R441 R442 R443

R444

I2445 R446,447 R448 R449

R450

R451,452 R453 R454 R455 R456

0687-2221 0819-0021 0687-4721

185A-26A

0687-4701

0687-5601 0690-2731 0758-0014 2100-0281 0758-0013

0687-1021

0

764 -0002

2

100

-0049

0

-00

210 0687-1231

0693-1011 0687-5621 0687-2721 0690-2231 0758-0015

54

Fk

&d,

comp,

R

fxd,

ww,

R

fxd,

comp,

R

fxd,

0.057

R

fxd,

comp,

R

fxd,

comp,

R

fxd,

comp,

R

fxd,

mfgl,

R

var,

ww,

R

fxd, mfgl,

R

fxd,

comp,

Not assigned

R:

fxd, mfgl,

R

var, lin,

R

var,

ww,

R

fxd,

comp,

R

fxd,

comp,

R

fxd,

comp,

R

fxd,

comp,

R

fxd,

comp,

R

fxd, mfgl,

2.2K

3

ohms

4.7K

ohm

47

56

27K

180

lin,

120

1K

7.5K

20K

500

12K

100

5.6K

2.7K 22K

220

ohms

*20%, 55

ohms ohms ohms

ohms

100

ohms

ohm

ohms ohms ohms,

ohms

ohms ohms

ohms

*lo%,

w

*lo%,

1/2

*lo%,

*5%, 1/2

*20%, 1-1/2

*5%, 1/2

*lo%,

*20%,

*5%,

2

w

1/2

2

1/3

*lo%,

*5%, 1/2

1/2

1

w

1/2

2

w

1/2 1/2

1

w

a

b

a

w

R457 R458 R459 R462 R463

R464 R465 R466 R467 R468

R469 R470

6-20

thru

R461

2100-0281 0758-0016

0687-1041 0

81 6

-00

11

0816-0015 0687-2211 0690-1531

0687-3911

2100-0005

0758-0016 0767-0008

R

var,

ww,

R

fxd,

mfgl,

Not assigned

R

fxd,

comp,

R:

fxd,

ww,

R

fxd,

ww, 50

R

fxd,

comp,

R

fxd,

comp,

R

fxd,

comp,

R

var,

ww,

Fk

fxd, mfgl,

R

fxd, mfgl,

#

See

introduction

lin,

300

lOOK

1K

ohms

220 15K 390

lin,

300 10K

to

100

ohms

ohm

ohms ohms

2K

ohms

this

ohms

*lo%,

ohms

eection

*20%, 1-1/2

*5%, 1/2

*lo%,

10

1/2

w

1/2

1

1/2

*lo%,

*5%, 1/2

*5%, 3

w

2

w

-

01255-1

HP 185B Service manual

Specifications and Main Features

Frequently Asked Questions

User Manual