HP 152A, 150A Service manual

OSClllOSCOPE

OPERATING

AND

SERVICING MANUAL

OPERATING AND SERVICING MANUAL

FOR

MODEL 150A

HIGH

FREQUENCY OSCILLOSCOPE

Serial

1190

and

Above

And

MODEL 152A

DUAL TRACE AMPLIFIER

Serial

1086

and

Above

,

275

PAGE MILL ROAD,

Copyright

HE

WLET T-PACKARD COMPANY

1956

by Hewlett-Packard Company

The information contained in this booklet i3 intended for the operation and maintenance of Hewlett-Packard equipment and is not to be used otherwise or reproduced without the writtenconsent Packard Company.

PAL0

of

the Hewlett-

ALTO,

CALIFORNIA, U.S.A.

'

15OAOO1-1

INTERNAL SWEEP:

MAGNIFICAT ION:

SYNCHRONIZATION:

SYNC CONTROL:

150A SPECIFICATIONS

SWEEP GENERATOR

24

calibrated ranges provide sweep speeds from 0.1

psec/cm to 5 sec/cm; accurate to within

A vernier control provides continuous adjustment of sweep speed between calibrated ranges and extends slowest sweep to 15 sec/cm.

5 calibrated ranges, X1, X5, X10, X50 and XlOO magni-

fies center portion of unmagnified trace; increases fastest sweep speed to

magnification and ranges retain accuracy of original sweep.

Internal, from line power or vertical input signal which causes 1/2 cm or more vertical deflection. External,

either capacitive or direct coupled with 1/2V p-p or more.

Sweep can be triggered from either

negative going voltage; the triggering voltage level of external sync signals

-30

to

+30

volts.

Switch position automatically provides optimum sync

stability for majority of uses.

2p

.02

XlOO

is

psec/cm except lp X50

magnification. X1 and X5

continuously adjustable from

39%.

a

positive- or

a

SINGLE SWEEP: SAWTOOTH OUTPUT:

GATE OUTPUT:

BAND WIDTH:

.

SENSITIVITY:

INPUT IMPEDANCE:

OUTPUT:

Switch in top access provides single-sweep operation. +20

to

-20

volt sawtooth output available from connec-

tor in top access.

20-volt positive pulse for duration of sweep available

from connector in top access.

HORIZONTAL AMPLIFIER

Direct current to 500 kilocycles.

5 calibrated ranges provide sensitivities from

volt/cm to 5 volts/cm. A vernier control provides

continuous adjustment between calibrated ranges and extends the minimum sensitivity to 15 volts/cm.

1 megohm shunted by

CALIBRATOR

1000-cycle square wave having 1-psec rise and decay time available

18 calibrated ranges provide from volts peak-to-peak, accurate to within

at

40

pfl.

front-panel connector

0.2

.

millivolt to 100

370.

0.2

I

,

I

,

!

t

I

!

TYPE:

CATHODE RAY TUBE

5 AMP-

P1,

potential

rr-cno-accelerator,

P2,

P7

.

or P11 screen. 5000-volt accelerating

flat face, available with

\

I

i

I

1

I

DEFLECTION PLATE CONNECTIONS:

INTENSITY MODULATION:

REPLACEABILITY:

POWER REQUIREMENTS:

SIZE: WEIGHT:

BANDWIDTH:

SENSITIVITY:

Both screw and pin-type terminals in top access re-

or

ceive wires tion to plates.

Terminals inside top access to receive +20 pulse for blanking CRT trace of normal intensity.

CRT bezel removes with graticule or CRT from the front panel.

CRT bezel provides firm mounting for standard oscilloscope cameras

115/230 VAC watts.

13-1/2" wide Net weight

@l52 DUAL TRACE AMPLIFIER

Direct Current to microsecond.

9

calibrated ranges provide sensitivities from

20 volt/cm, 57'0. Vernier control provides continuous adjustment between calibrated ranges and extends the minimum sensitivity to 50 volts /cm.

special connector assembly for connec-

.

+lo%,

x

17-1/411

80

pounds; shipping weight

50/60

high x 25" deep.

10

megacycles; rise time 0.035

150

twist for replacement of

cycles, approximately500

104

pounds.

0.05

to

INPUT IMPEDANCE:

I

,

1

I

i

DUAL TRACE PRESENTATIONS

1'

i

!

I

i

I

i

I

1

megohm shunted by

Simultaneous traces obtained either by alternate sweep

or

ing

ping lines between traces are blanked.

Channels are completely independent and have identical operating controls

Pos-Up-Pos Down switch provided.

by 100-kilocycle chopping,

40

.

ppf

each channel.

as

selected. Chop-

TABLE OF CONTENTS

FOR

MODEL 150A AND MODEL 152A

HIGH FREQUENCY OSCILLOSCOPES

Par

1-1 1-2 1-3 1 -4 1-5 1-6

2-1 2 -2 2-2A 2-2B 2-2c

2-2D 2-2E 2-3 2 -4 2-5

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

3-6 3-7 3-8

-9

3 3-10

3-1 1 3-12 3-13

4-1

a

.

SECTION

GENERAL DESCRIPTION

General Information. Damage Power Line Voltages Power Cord Cooling Overload Relay

OPERATING INSTRUCTIONS

High Voltage Time Delay Controls and Terminals Internal Sweep Controls Horizontal Input Controls. Dual Channel Amplifier Controls CRT Panel Controls Top Access Controls Operating Procedures

'Vertical

Use of Chopped or Alternate Sweep

THEORY

General Content Overall Operation Synchronizing Circuit Sweep Generator Feedback Integrator and

Diode Switch Schmitt Trigger Circuit Horizontal Amplifier.

Main Vertical Amplifier Model 152 Dual Trace

Amplifier Plug-In Unit Calibrator Regulated Low-Voltage Power Supply Re gulate d High-Volt age Power Supply Single Sweep and Delayed Sweep Operation

Introductory

in

Transit

.

. . . . . .

.

. . . .

. .

SECTION I1

. . .

AC

.

. .

or DC Coupling

. . . . .

SECTION

OF

111

OPERATION

. . .

. .

. . . . . . . .

.

. . . . . . .

. . .

SECTION IV

MAINTENANCE

. . . . . . .

I

. .

. . .

.

. .

.

. .

.

. . .

. .

. . .

. . . .

. . .

. .

.

. .

.

. .

.

. .

.

Page

1-1 1-1 1-1 1-1 1-1 1-1

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

2-2 2-3 2-3 2-3 2-3

2 -4

3-1 3-1 3-3 3-5

3-6 3-7 3-7 3-8

-9

3 3-1

3-1 1 3-13 3-13

4-1

Para.

4-2 4-3

-4

4 4-5

4-6 4-7

4-8

4-9 4-10 4-11

4-12

4-12A

4-12B XlOO Magnification

4-12C X5 to XlOO Magnification

4- 12D Main Horizontal Amplifier

4-13 Adjusting the Ext. Horiz. 4- 13A Horiz . Balance 4-13B Ext. Horiz. Input 4-13C Ext. Horiz. Input

4-14 Adjusting the Sync Circuit 4-15 Adjusting the Preset Sensi-

4-16 Calibrating the Sweep 4- 16A Sweep Amplitude

1

4-17 Adjusting Gain and Fre-

4-18 Adjusting Model 152A 4-18A Vertical Centering 4- 18B Neutralizing Adjustments

4-18C Output Frequency

Replacing the Air Filter Removing the Cabinet Connecting for 230-Volt Power Lines Servicing Etched Circuits Tube Replacement Chart Isolating Troubles to Major Sections Adjusting the Low-Voltage Power Supplies Adjusting the High-Voltage Power Supply Replacing and Adjusting theCRT Adjusting the Calibrator

Adjusting the Main Horizontal Amplifier. Main Horizontal Gain Adjustment

Calibration Centering and X1 Centering. Frequency Response

Adjustment Input Preamplifier. Adjustment. Volts/CM Calibration

tivity of the Sweep Generator

Generator Adjustment quency Response

Vertical Amplifier Trace Amplifier. Adjustments

Response Adjustment

. . . .

. . . . .

.

. . . . . .

.

. . . . . .

.

. . . . .

.

. . .

.

. .

. . .

.

. .

. . .

.

. . . .

. . .

. .

.

. .

.

. . . . .

of

Main

. . .

Dual

. . . .

. .

.

. .

.

. .

.

. .

.

. .

.

Page

1

44-1

4-1 4- 1 4-3

4-3 4-3

4-9 4-9

4-11 4-11 4-11 4-13 4-13

4-14

4-15 4-15 4- 15

4-17 4-17

4-18

4-

18

4-18

4-21 4-2 1 4-21

4-21 4-23

1-1

GENERAL INFORMATION

SECTION

I

GENERAL DESCRIPTION

1-4

POWER CORD

The Model 150A dc to 10 MC oscilloscope

a

general purpose oscilloscope employing

5-AMP mono-accelerator type cathode ray tube, with unitized, plug-in construction for maximum accessibility and flexibility. It

can be used with either internal or external

sweeps which can be either internally or externally synchronized. The horizontal amplifier incorporates magnification circuitry

is

which sweeps up sweep range extends from .02 bsec/cm to 15 sec/cm.

The Model 150A has been designed for use

with units to perform many different functions but for the purpose of explaining scope operation in this manual, the Model 152A Dual Channel Amplifier employed, Since the control layout on the front panel has been carefully organized and labeled for convenient operation, most controls will be self-explanatory. However major controls will be discussed completely in the operating section of the manual. A large fold outview of the panel Section I1 with

s

cr ibed

capable of expanding basic internal

to

100 times. Thus the internal

a

variety of vertical amplifier plug-in

it

will be assumed that

is

included in

all

operating controls de-

.

is

The three conductor power cable supplied

withthe instrument

a

ized three prong male connector recommend-

ed by the National Electrical Manufacturers'

Association. The third contact

round pin added to plug which grounds the instrument chassis when used with the appropriate receptacle.

To use this plug in outlet an adapter should be used to connect the NEMA plug to the two contact system. When the adapter tion becomes

which can be connected to the outlet mounting box for the protection of operating personnel.

,

1-5

COOLING

The Modell5OA employs a forced draft cooling system to maintain satisfactory operating

temperatures within the case. The

and

air

filter

case, and adequate cooling will take place

,

long

as

the case ing obstructs the filter. Generally, the height of the cabinet feet provide such clearance.

Thus the Model150A can be used in fined bench set-up of the cabinet tures are not extreme.

is

terminated in a polar-

is

a

standard two-blade ac

a

standard two contact

is

used the ground connec-

a

short lead from the adapter

located under the instrument

is

on the instrument and noth-

as

long

as

the underside

clear, and ambient tempera-

an offset,

air

intake

as

a

con-

1-2

DAMAGE IN TRANSIT

After unpacking this instrument should any The Model shipping damage become evident, refer to the reduces the output voltages 1lClaim for Damage in Shipment" paragraph ply when: on the warranty sheet in this manual.

1-3

POWER LINE VOLTAGES

The Oscilloscope, like other @ instruments, is

shippedfrom thefactory wiredfor 115 volt ac line operation unless otherwise specified in the order. However, the instrument may

also be operated from a 230 volt ac line source if

the proper conversion

transformer. This conversion

is

described in the Maintenance section.

is

made to the power

is

simple, and

1-6

OVERLOAD RELAY

150A

1.

)

Any series tube on the d'-c heater string

strument

2.)

A plug-in vertical amplifier removed while the instrument

is

on.

3.)

A short circuit or excessive loading of any positive-voltage supply occurs.

has an overload-relay which

is

removed while the in-

is

on.

1-1

of

the power

SUP-

is

i

SECTION

OPERATING INSTRUCTIONS

2-1

HIGH VOLTAGE TIME DELAY

The Model 150A applies voltage only to

tube filaments for about

it

turn warm up before tube plate voltages and CRT high voltages are applied.

is

recycle before the instrument returns to operation.

2-2

The front panel arrangement and operating controls are shown in the fold out illustration, Figure 2-1. The description of the operating controls should enable you to operate the instrument of oscilloscope technique. However,

plete description of control function follows:

on. This delay provides an adequate

turned off for any reason this delay will

CONTROLS AND TERMINALS

if

you have a basic knowledge

30

seconds after you

If

the instrument

2-ZA INTERNAL SWEEP CONTROLS

SWEEP TIME/CM

Amulti-position switchwhich selects any one of twenty four calibrated sweep speeds from

0.1 pec/cm to5 sec/cm. This switchis sociated with a concentric VERNIER which

provides continuous adjustment of sweep

speed between steps, and in the full counterclockwise position extends the sweep time to

is

15 sec/cm. When the VERNIER

clockwise position (GAL),

cuit and the sweep time

k370

as

read

on

the SWEEP TIME/CM dial.

INT. SWEEP MAGNIFICATION Afive position magnification control, X10, X50, and X100. The Xlposition provides calibrated sweep speeds TIME /CM switch. Other positions indicate degree of expansion taking place about the

vertical centerline on the scope graticule. Whenever the sweep the SWEEP MAGNIFIED lamp will light. The fastest calibrated sweep time of

is

obtained by setting the SWEEP TIME/CM

switch to

.1

or

.2

psec/cm and setting the

it

is

calibrated within

as

read onthe SWEEP

is

magnified beyond X1

in the full

out of the cir-

0.02

pec/cm

a

X1,

its

com-

as-

X5,

II

magnifier on X5 or exceed the fastest calibrated sweep time, the MAGNIFIER UNCALIBRATED reminder lamp will light. It will also light with 1 psec/cm X50 and 2 psec/cm X100.

SYNC Afour position switch which enables the sweep to be triggered either internally or externally. Internal triggering can be accomplished

a

from applied vertical input signal of sufficient amplitude to produce nal triggering can be effected by signals having amplitudes greater than the low frequency cut sync input circuit it low frequency sync signals. Concentric with the SYNC switch

SWEEP MCDE

A

bias of the sweep generator. As the control

is

tion, the sweep generator will pass from

free running (FREE) condition to a condition where triggering the extreme counterclockwise position the

control switches into

PRESET provides optimum triggering bias for nearly

TRIGGER LEVEL A continuous control which selects the ampli-

tude level of the sync signal where trigger-

ing occurs. For external synchronizing sig-

nals therange of this controlis from

-30

at

complex waveforms. See Figure 2-2.

TRIGGER SLOPE A two position switch concentric with TRIGGER LEVELwhich permits triggering to occur on either the positive of internal, external or line voltage sync signals. See Figure 2-2.

EXT

A

which are connected in parallel and receive

external synchronizing signals.

line voltage signal or (INT) from an

is

advisable to use

continuous control which adjusts the input

rotated from the extreme clockwise posi-

all

sync applications.

volts, allowing the sweep to be triggered

any point within this range on simple or

SYNC

pair of binding posts and a BNC connector

INPUT

X1O

respectively. If you

a

5mm deflection. Exter-

0.

5 volt. Since

off

of the ac coupled

is

approximately 200 cps,

EXT

DC for external

is

the SWEEP MODE control.

is

required (TRIGGER). At

a

PRESET position.

or

negative slope

+30

to

a

2-1

2-2C

DUAL

VERTICAL PRESENTATION A four position switch which selects the desired vertical channel or desired dual channel presentation.

CHANNEL AMPLIFIER CONTROLS

This switch

is

labeled:

FIGURE 2-2

2-2B

HORIZONTAL INPUT CONTROLS

EXT HORIZONTAL INPUT

a

A pair of binding posts and which are connected in parallel and receive externally applied sweeping signals to drive the horizontal amplifier. The amplifier pass

is

band

from dc to

500

KC.

BNC connector

A ONLY

B ONLY

ALTERNATE

CHOPPED

POLARITY

A four position switch which allows the input

signal polarity to be displayed either up or

down on the scope, and which selects either AC or

VERTICAL POSITION

A continuously adjustable control, concentric with POLARITY, which adjusts the vertical position of the input signal. One for each

channel.

DC

The output of the A channel applied to the vertical amplifier.

The output of the B channel applied to the vertical ampli-

fier.

The two channels are alter-

at

nated paragraph 2-5.

The two channels

at

a

KC.

composed of five microsecond segments spaced five microseconds apart. See paragraph 2-5.

coupling. One for each channel.

the sweep rate. See

are

switched

free running rate

The

two

traces are each

of

100

is

EXT INPUT VOLTS/CM A five position attenuator calibrated from .2 volts/cm to 5 volts/cm which establishes the input

This switch VERNIER which provides continuous ad just ment between steps and reduces the input sensitivity to 15 volts /cm in the full counterclockwise position. When the VERNIER

the full clockwise (CAL) position, the circuit and the VOLTS/CM switch brated with

HORIZONTAL POSITION

A multi-turn control which changes the horiz-

ontalpositionof the trace. It covers the range

in several turns to let you make fine adjustments under high magnifications of an internal sweep.

sensitivity of the horizontal amplifier.

is

associated with a concentric

is

it

is

out of

is

cali-

+30/0.

in

VOLTS /CM A nine step attenuator which selects the input

sensitivity of the vertical amplifier.

tivities range from. 05 trolts/cm to 20 volts/

a

cm in

-

VERNIER

‘CM

for each channel.

A-BAL and B-BAL Screwdriver adjustments for adjusting the dc balance of each vertical amplifier. ure

A-CAL and B-CAL Screwdriver adjustments for setting the gain of each vertical amplifier.

2-2

5-1-2 sequence.

is

in the CAL position the VOLTS/

attenuator is calibrated within

2-11.

Whenthe concentric

Sensi-

+3oJO.

One

See Fig-

2-2D

CRT PANEL CONTROLS

FOCUS

01s

Contr

trace resolution,

RESET A terminal which can receive an external pulse to rearm the single sweep circuit. Pulse

characteristics required

peakwithno overshoot;

=

+15 to +25 volts

2

to 4 pseconds width.

INTENSITY Controls trace brightness.

SCALE LIGHT Adjusts brightness of graticule lines.

CALIBRATOR

a

at

1000

the

rise

A multi-position switch which adjusts

cps square wave from 0.2 millivolts to 100

volts in

+3

of adjacent terminal and can be used to calibrate the deflection sensitivity of the vertical and horizontal amplifier and decay times are each less than 1 micro-

second. The square wave output may also be

used to adjust the divider probe for frequency

response.

a

2-5-10 sequence with an accuracy

70.

The output voltage appears

.

Square wave

2-2E TOP ACCESS CONTROLS

The following controls and terminals are accessible through the top access door of the instrument cabinet.

Horizontal and vertical deflection plates.

A terminal for CRT intensity (Z-axis) modulation

FUSE

Line fuse Thermal cutout with resetting button.

2-3

OPERATING PROCEDURES

Basic operating procedures are described by illustrations

steps in eachcase. The

are complete. Others are arranged to supplement the tions possible in using the oscilloscope. index to these illustrations follows:

FIG.

2-3 2 -4 2-5 2-6

2-7

2

-8

2

-9

2-10 2-1 1

2-12 2-13 2-14 2-15 2-16 2-17

(Fl)

6-1/4 amp slo-blo.

which are keyed to procedural

first

twoprocedures

first

two by showing the varia-

TITLE

Internal Sweep Internal Sweep Internal Sweep Magnification External Horizontal Input

Vertical Input Adjusting Divider Probe Removing CRT Bezel Aligning Scope Trace with Graticule Vertical Balance Adjustment

Direct Connection to

Capacitive Coupling to CRT Plates Single Sweep Operation

Delayed Sweep Operation

Vertical VOLTS /CM Calibration

External Intensity Modulation

--

Internal Sync

--

External Sync

--

Dual Trace

CRT

Plates

An

SAWTOOTH OUT

A terminal which provides voltage corresponding to the sweep.

GATE OUT A terminal which provides voltage for the duration of the sweep.

SINGLE-NORMAL A switch which selects either normal or sin-

gle sweep operation. In single sweep posi-

tion the circuits are arrangedto sweep once

a

after tive until manually or

The ARMED lamp lights when the single sweep circuit

trigger signal and then remain inopera-

is

ready for a trigger.

a

sawtooth output

a

positive gate

electronically reset.

2-4

VERTICAL AC OR DC COUPLING

Under most conditions AC coupling will be used.

without regard for the dc levels involved. In

the AC position the input signal (vertical or

external sync)

through

component from the input wave. This coup-

ling circuit has

cps; however, to avoid degrading input pulses or square waves below 10 cps to use dc coupling.

When you want to look to

rundown in circuit work, or in mechanical work where the output from

a

It permits high gain to be employed

is

coupled to the instrument

a

capacitor which removes the dc

a

low frequency cut off

it

is

advisable

at

waveforms relative

a

dc level; for example, observing a Miller

a

transducer has

dc component; use dc coupling.

2-3

at

2

2-5

USE

OF

CHOPPED

OR

ALTERNATE SWEEP

CHOPPED and ALTERNATE VERTICAL PRG

two

SENTATIONare used topresent

electrical phenomona, which are related in

frequency or rate of recurrence, to the

cilloscope CRT for simultaneous viewing. ALTERNATE may be used whenever sweep time and rate of recurrence are rapid enough

is

and screenpersistence vent objectionable flicker. CHOPPED PRESENTATION should be used NATE position

on the screen as the inputs are switched after

a

flickering effect

long enoughto pre-

if,

separate

os-

in the ALTER-

is

noticeable

each sweep. When two related signals are

being presented to the oscilloscope for

multaneous viewing using either CHOPPED or ALTERNATE VERTICAL PRESENTATION the 150A should be synchronized externally.

Insome cases different input waves not related infrequency. In this instance the 150A may be synchronized internally, triggering automatically one signal then from the other

is

dure may cause noticeable deterioration of the

quality may be improved byadjusting the VERTICAL POSITION controls

not ordinarily recommended since

of

it

may be desirable to view two

first

.

This proce-

the presentation. Quality generally

so

that the traces overlap.

si-

from

it

2-4

INTERNAL SWEEP - INTERNAL SYNCHRONIZATION

-0-

I

1.

Place vertical input signal into plug-in am-

plifier.

2.

If dual trace amplifier CAL PRESENTATION selector to put; assume one input is used.

3

.

Adjust VOLTS/CM selector for desired sensitiv it

y

.

4.

Set SYNC selector to INT.

is

used, set VERTI-

A

or

B

in-

FIGURE

5.

Set HORIZONTAL SENSITIVITY to INT

x1.

6.

Select desired sweep speed.

7.

Set TRIGGER LEVEL to zero.

8.

Set TRIGGER SLOPE for triggering on positive or negative slope sired.

9.

Set SWEEP MODE to PRESET.

2-3

of

input wave

SWEEP:

as

de-

INTERNAL SWEEP - EXTERNAL SYNCHRONIZATION

1.

Place vertical input signal into plug-in am-

plifier.

2.

If dual trace amplifier

CALPRESENTATION switch toproper input.

Assume one input

3

.

Place sync signal into EXT SYNC INPUT terminals

4.

Place HORIZ SENSITIVITY to INT SWEEP X1.

.

is

used (A or

used, set VERTI-

B).

FIGURE

5.

Select desired sweep speed with SWEEPTIME/CM switch.

6.

Set TRIGGER LEVEL to zero.

7.

Adjust SYNC selector to AC or DC quired (see paragraph

8.

Place SWEEP MODE in PRESET.

2-4

2-4).

as

re-

INTERNAL SWEEP MAGNIFICATION

I

1.

Select sweep speed with SWEEP TIME/CM switch.

Place

2. of SWEEP TIME/CM switch

3.

Set HORIZ SENSITIVITY to INT SWEEP X1 (X1

4.

Adjust horizontal position of want ticular wave in

nification. UNCAL lamp stays off)

VERNIER in CAL when direct reading

is

the unmagnified sweep position).

to

magnify a portionof a wave or a par-

a

train, place wave

SWEEP TIME/CM MAGNIFICATION

Actual sweeptime/cm=

.

Olpsec / cm;uncalibr ated lamp will light. In-

crease sweep time or reduce degree of mag-

=

is

desired.

of

G

If you

inter-

X50=

trace.

.5 psec/CM

X50 MAGNIFICATION

psec/cm

.5

est under vertical graticule center line with HORIZ POSITION control.

5. Switch HORIZ SENSITIVITY to desired magnification (X5 or above).

6.

SWEEP MAGNIFIED indicator will light.

7.

If

combination of sweep magnification exceeds maximum calibrated sweep speed FIER UNCALIBRATED indicator will light.

SWEEP TIME/CM

Actual Sweep Time

(Sweep

time

>

.02pec/CM,MAGNIFIER

speed and degree of

(.02

peconds/cm) the MAGNI-

=

.5 psec/CM

=

X10

=

.5 psec/CM $(XlO)

=

.05

psec/CM

FIGURE

2-5

EXTERNAL HORIZONTAL INPUT

(if

VLINILI

1.

Insert external horizontal signal.

2.

Select desired

side

of

HORIZONTAL SENSITIVITY control,

sensitivity

on

EXT

INPUT

FIGURE

3.

Adjust horizontal position.

4.

Turn SYNC selector to an EXT position.

5.

For vertical input see Figures

2-3

2-6

and

2-4.

VERTICAL INPUT - DUAL TRACE

1.

Set to A only.

2.

Place one of two input signals intoINPUT A.

3.

Adjust deflection sensitivity with VOLTS /CM

switch. When VERNIER reads CAL, accuracy of VOLTS/CM switch

4.

Select polarity of presentation.

negative or positive portion of input wave

displayed up or down.)

is

+3%.

(

Whether

is

FIGURE

Adjust vertical position of trace near upper

(or lower) portion of scope face.

5.

Switch to INPUT B and repeat above procedure on

6.

Switch to ALTERNATE or CHOPPED for dual trace presentation.

B

side of panel.

(See paragraph

2-7

2-5.

)

..

Connect theAC-21AProbe to the desired ver-

lo

tical input, and set the VERTICAL PRESENTATION selector to the corresponding input.

Set the CALIBRATOR selector to

2.

vertical VOLTS/CM selector to Set the SWEEP TIME/CM selector to. 5 MIL-

3.

2.

.05.

LISECOND/CM; set the SYNC selector to INT, the SYNC control to PRESET.

Touch the probe to the CALIBRATOR connector

4.

and observe the 1-kc square wave.

I

Set the

.-

Loasen probe locknut by unscrewing.

5.

Tune probe to obtain flattest top on square

6.

wave by turning rear flange Tighten locknut to retain adjustmenti

7.

on

probe.

t:

/

II

'

FIGURE

2-8

REMOVING CRT BEZEL

LOCK

RELEA

The CRT bezel contains the filter and graticule shields; cept oscilloscope camera equipment without

adapters of any kind.

cathode ray tubes the bezel must be removed,

it

has also been designed to ac-

To

change filters or

FIGURE

To

remove bezel:

1

.

Depress lock release button, and twist bezel

counter clockwise about 15 degrees

2.

Pull bezel straight from panel

2-9

.

as

shown.

ALIGNING SCOPE TRACE

WITH

GRATICULE

Alignment complished through access hatch without removing instrument from case.

of

CRT

with graticule may be ac-

FIGURE

(2)

Fiber lever

itudinal positioning clamp

(l),

controls both radial and

using screwdriver.

2-10

of

CRT

and

is

locked by

long-

VERTICAL BALANCE ADJUSTMENT

Procedure given for B channel, but

A

for

1. Set SWEEP MODE control to FREE RUN.

2

channel.

.

Set VERNIER to minimum (full counterclock

.

wise)

is

same

FIGURE

3

.

Center trace with VERTICAL POSITION control.

4.

Switch VERNIER to

5.

Adjust B-BAL control to return trace to

center of scope.

2

Repeat steps

2-11

to 5 until trace remains centered.

CAL

(full clockwise).

DIRECT CONNECTION

//

EXTERNAL INPUT SIGNAL

I

TO

DEFLECTION

PLATES

'R282

IM

CAUTION

oscilloscope operate

approximately +250 volts. Therefore there canbe no commonchassis connection between

the signal source and the oscilloscope. In

most cases the signal source chassis assume the deflection plate potential. Turn off the to deflection plate terminals.

To connect an external signal directly to ver tical deflection plates:

A. Balanced Input

1,Connect signal to terminals A and

-

The deflection plates of the

at

a

d-c potential of

will

'

instrument before making connection

,

E.

FIGURE

-

2.Relocate leads from as shown by dashed lines.

B.

Single-Ended Input

1.Connect the signal to A for + up deflection (to E for + down deflection).

2.

Connect an appropriate bypass capacitor betweenC and (between C and Afor Signal source return connects to A, whichever is bypassed.

3.

Relocate leads from

as

shown by dashed lines.

2-12

F,

I,

D3

E

for t up deflection

+

down deflection).

F,

I,

D3

and

E

D4

or

D4

CAPACITIVE CONNECTION

EXTERNAL

INPUT

SIGNAL^

.

(SINGLE-

/

TO

DEFLECTION

-R282

IM

PLATES

CAUTION

-

Turn off instrument before making connection to deflection plate terminals.

ac

couple a signal to the vertical deflection

To

plate

:

A. Single-Ended Input

1.

Connect external signal to B for t up deflection (to D for and the signal return to

2.

Connect an appropriate bypass capaci-

tor betweenC and E for

t

down deflection)

C.

t

up deflection

(between C and Afor t down deflection).

3. Connect an appropriate d-c blocking

FIGURE

capacitor betweenA and B for flection (between D and

deflection).

F,

4.Relocate leads from

as

shown by dashed lines.

I,

B. Balanced Input

1.

Connect external balanced signal to minals B and D.

2.

Connect appropriate d-c blocking pacitors between terminals A and B and between terminals

3.Relocate leads from

as

shown

by dashed lines.

D and

F,

I,

2-13

t

E

up de-

for t down

D3, and D4

E.

D3, and D4

ter-

ca-

SINGLE SWEEP OPERATION

PP

THERMAL OVERLOAD SWITCH

(MANUAL RESET

1

1.

Set selector inside top access to SINGLE.

2.

Select sweep speed.

3.

Set SYNC switch to INT. and SWEEP MODE MODE control

to PRESET.

4.

Select desired vertical sensitivity.

5.

Adjust TRIGGER LEVEL to ZERO and

SLOPE

it

TRIGGER LEVEL in NORMAL operation.)

as

may be convenient to establish desired

desired.

(In

some applications

FIGURE

6.

Switch SWEEP MODE control out ofPRESET and back to PRESET to arm sweep

circuit

7.

Indicator should light When input signal

fire

once, indicator

and sweep will remain locked out until re-

set

as described in step

8.

Resetting can be accomplished by placing

1-4

pec

into RES ET terminal

2-14

.

width,

as

soon

as

is

returned to PRESET.

is

received, sweep will

(7)

will extinguish,

6.,

or

t15

to

t25

volt peak pulse

.

SWEEP

4

DELAYED SWEEP OPERATION

D

OUTPUT

DELAY GENERATOR

-hp-

2

OR

I2

INPUT

J3

1.

Set selector inside top access to NORMAL.

2.

Select sweep speed.

3.

Set SYNC switch to INT and SWEEP MODE to PRESET.

4.

Select desired vertical sensitivity.

5.

Adjust TRIGGER LEVEL and SLOPE for desired triggering.

6.

Switch selector to SINGLE.

7.

Connect output of DELAY GENERATOR to RESET terminal inside top

access.

8.

Connect signal to be observed to scope in-

(Channel A or

put.

9.

Connect trigger source to input of delay generator. Trigger-source signal in some applications may be same observed(step signal. This signal serves sweep retriggering source. (See SINGLE

SWEEP OPERATION.

10.

It may be desired to have the sweep immediately of awaiting the arrival of signal to be observed.

1 through

SWEEP MODE control to FREE RUN.

at

To

accomplish this, follow steps

9,

except that after step

8)

end

B

as

desired.)

as

or

it

may be some other

)

of

delayperiod instead

signal

as

a

to

be

single

start

6,

set

FIGURE

2-

15

VERTICAL VOLTS/CM CALIBRATION

This procedure assumes that vertical . alance

adjustments (Figure 2- 11) have been made.

1.

Connect CALIBRATOR output (or any accurate ac voltage) to the vertical INPUT (assume B in this case).

2. Set CALIBRATOR to the .2 volt position

if

2 volt position

(use

AC-21A probe

used).

3.

Set VOLTS/CM switch to

.05,

and switch

FIGURE

VER

TIER to CAL.

4.

Sync scope internally.

5.

Use convenient sweep speed (app. .5 MS/ CM).

6.

is

Adjust R589 (accessible through frontpanel as shown) to obtain a verticaldeflection of exactly

4

centimeters on scope graticule.

Repeat procedure for channel A.

2-16

EXTERNAL INTENSITY MODULATION

I

To intensity signals

:

1.

Set

INT.

modulate the CRT with external

Z

-

EXT. Z switch to EXT.

FIGURE

Z.

Connect modulating signal to input ter-

2.

minals. peak will normal intensity. brighten the trace.

2-17

A

positive voltage of

blank

the CRT trace from

A

negative input will

20

volts

1

INT.

SYNC

I

VERTICAL

CRT

PLATES

\

HORIZONTAL

AMPLIFIER

HORIZONTAL

FIGURE

CAT

PLATES

3-1

TO

ASTlCMATlSY

3

-0

SECTION

111

THEORY

3-1

GENERAL CONTENT

This section contains a brief description of

the overall operationof the 150A Oscilloscope, descriptions of each major section and detailed explanations of the Feedback Integrator Sawtooth Generator andSchmitt Trigger. The

is

description for each major section ported by voltage and when necessary, a switch detail diagram,

at

the rear of the manual. The material in

this section

3-2 Overall Operation and Circuit 3-3 Synchronizing Circuit

3-4 Sweep Generator 3-5 FeedbackIntegrator and Diode

3-6

3-7

3-8 Main Vertical Amplifier 3-9

3- 10 Calibrator 3-

3- 12 Regulated High-Voltage Power

3-13 Single Sweep And Delayed

3-2

OVERALL OPERATION

The simplified block diagram in Figure 3-1

shows the basic signal circuits in the Model 150A Oscilloscope: the Horizontal Amplifier, Sweep Generator and Cathode Ray Tube.

a.

Vertical Amplifier - The verticalamplifier receives the input signal, amplifies

it,

and drives the vertical deflection plates.

It

provides attenuation of the input signal;

determines the direction of spot deflection

a

for the vertical positionof the spot on the screen;

supplies and incorporates

put waveform.

its

complete schematic diagram,

-

resistance-tube-location diagram

is

as

follows:

Locations

Switch Schmitt Trigger Circuits Horizontal Amplifier

Model 152A Dual Trace Amplifier

Plug-In Unit

11

Regulated Low-Voltage Power

s

UPPlY Supply Sweep Operation

Vertical

given input signal polarity; determines

a

signal for internal synchronization;

a

0.25 pec delay in the in-

Amplifier,

sup-

OF

OPERATION

The complete Vertical Amplifier circuit in three separate parts: the final amplifiers, located on the upper board; the intermediate amplifiers on the lower board on the instru-

ment chassis, input-preamplifier attenuators, phase inverters and beam positioners are on the etched

board in the Vertical Amplifier Plug-In Unit.

All connections to the plug-in unit are made through two multiple-contact connectors

,

the plug-in connections to the Main Vertical Amplifier on the instrument chassis are made through

a

tube-socket connector, while the signal path

between the intermediate and power amplifier

stages is made thrbugh the special coaxialcable delay lines.

b. Horizontal Amplifier

amplifier receives the sweep voltage either from the HORIZONTAL INPUT jack or from the internal sweep generator, amplifies

it,

and drives the horizontal deflection plates. It provides attenuation of the HORIZONTAL INPUT signal or MAGNIFICATION of the internal sweep and determines the horizontal

position of the spot on the screen.

The complete Horizontal Amplifier consists of the main Amplifier, and (used only for external signals applied to the HORIZONTAL INPUT connector). The preamplifier stage includes the VOLTS /CMportion of the HORIZONTAL SENSITIVITY selector switch and

is

set

to one of the MAGNIFICATIONpositions. The MAGNIFICATION circuit of the HORIZONTAL SENSITIVITY selector

Horizontal Amplifier. The sawtooth sweep

is

applied to the Main Horizontal Amplifier while external signals the HORIZONTAL SENSITIVITY switch and the preamplifier.

The complete Horizontal Amplifier circuit

located on the single etched board on the lefthand, swing-out chassis. Connections to the chassis connectors on the board.

are

as

shown in Figure

is

pushed into position. Power

-

The horizontal

a

preamplifier

is

not effective when the switch

is

in the Main

are

first fed through

made through two tube-socket

3-2,

is

the

as

is

-1

3

INPUT

LTTENUATORS

-

VERTICAL

AMPLIFIER

(PLUG-

(51W

TIUIICU

IN

I

)

VtRUltR

10

MAIN

VERTICAL

AMPLIFIER

VI-V6

INTERNAL-SYNC

AMPLIFIER

TRIGGER

-

YlRTlCIL

CRT

-

t4lSVOC

lUIRtCl

t

400

t

260

t

I30

-

82

-

150

UII8RIIOR

VOC

YOC

VOC

VQC

VOC

REGULATED

UIW-VOLTAGE

POWER

SUPPLIES

SEE

mirn

survu

8LOCl

OIIUU

I

SWEEP

GENERATOR

VlO-Vl7

IStl

Otllll

BLOCI:

UITWTU

SlttP

01IORA1I

UUBLIIIIXt PULSt

CRI

INTlMSlll

WWLl

10

INltISlTl

-5OOOVDC

1,,,,1$

HICH

VOLTAGE

POWFR SUPPLY

V27-VJO

d’(lllTtlSITII

PREAMPLIFIER LMPLlFlER

HORIZONTAL

FIGURE

3-2

L

UORIZQITIL

cnr

-

c.

Sync Circuit - The Synchronizing Circuit

receives a sync signal either from the

Vertical Amplifier for internal synchroniza-

from the EXT. SYNC INPUT connector

tion; for external synchronization, or from an internal 6.3-volt source for line frequency syn-

chronization. The Sync Circuit amplifies input signals, determines the input voltage level and polarity of input sync signal which

start

will reliable sync pulse for operation of the Saw-

tooth Generator.

a

sweep; and supplies a fast

all

and

switch. fied and inverted in V8A, or are amplified without inversion in V8B. The desired polarity of sync signal that the sweep plate by the TRIGGER SLOPE control. A negative-going signal lowing Schmitt Trigger positive input-sync signals from the plate of V8B while negative signals

are

All

incoming sync signals

is

then taken from the appropriate

is

required for the fol-

taken uninverted from

is

tobeusedto

V9;

consequently,

are

taken inverted

V8

A.

are

ampli-

start

-

d. Sweep Generator

receives a negative starting pulse from the Sync Circuit and generates be fed to the Horizontal Amplifier. The Feedback Integrator determines the basic sweep time per centimeter, the Retriggering Bias

Controldetermines the sensitivity of the generator to incoming sync signals and provides

either single or repetitive sweeps. The sweep generator also supplies an unblanking pulse

a

to the CRT and

sawtooth flyback) to the Dual Channel Verti-

cal

Amplifier Plug-In Unit for ALTERNATE

operation.

The complete Sweep Generator and Sync Cir-

is

cuit

the right-hand, swing-out chassis.

nections to this chassis

three tube-socket connectors and three pin

connectors on the board.

e. The CRT operated at -5000 volts. The 5AMP may be

obtained with four different phospors: green medium; plied with the 150A)

short. All are interchangeable with little readjustment and the tube

through the front panel. The mono-accelerator anode makes possible matism adjustment (located inside the access hole) which requires no resetting when adjusting the FOCUS or INTENSITY. The deflection plate terminals located on the peri-

phery of the tube

movable jumpers directly to the Main Vertical Amplifier.

3-3

The Synchronizing Circuit consists put Amplifier-Phase Inverter (V8) and Schmitt Trigger wave shaper

ceives synchronizing signals either from the EXT. SYNC INPUT connector on the panel, the Main Vertical Amplifier, or from the line frequency,

located on the single etched board on

mono-accelerator tube with the cathode

SYNCHRONIZING CIRCUIT

as

timing signal (during each

-

The CRT

2,

green long; (normally sup-

are

selected by the SYNC selector

The Sweep Generator

a

sawtooth to

are

made through

is

a

type SAMP,

7,

blue long; the

is

easily changed

a

simple astig-

connected through

(V9).

All

11,

of

V8

con-

1,

blue

re-

an In-

re-

The TRIGGER LEVEL control shifts V8's operating potentials in apositive or nega-

so

tive direction nal meets the trigger-voltage level of the following Schmitt Trigger with more or less

sync voltage input.

Sync Schmitt Trigger

going input voltage to

tion, and produces

start

by the negative-going portionof the sync pulse,

V9

(which normally follows on

form) before

start

age moved only once in one direction

produce

V9, and no more sweeps would be possible

untilV9 was returned to somewhat beyond

original

tion of the hysteresis in

a

The negative output pulse from V9B entiated, producing

which

Triggering Sensitivity Ad jus tment R 66 varies the gain of V9A to vary the hysteresis of the trigger circuit, thus determining the input voltage level which will cause the trigger to switch

Symmetry Adjustment bias level on V9B to shift the hysteresis of the trigger tive direction. This adjustment positions the hysteresis voltage limits equally above and below the 0-signal input voltage level. Since both controls affect the gain of the circuit,

a

adjustment of either one however, varying the plate load resistance of V9A varies the degree of hysteresis predominantly, while varying the grid bias on V9B varies the voltage position of the hyster-

esis

the Sweep Generator. Once triggered

must be reset by a positive-going voltage

another sweep.

a

single sweep, but would not reset

state

starts

state,

area

predominantly.

an amplified input sync sig-

V9

requires a negative-

start

the desired opera-

a

reliable output pulse to

a

repetitive wave-

it

can again be triggered and

If

the input sync volt-

(see para. 3-6 for an explana-

a

Schmitt Trigger).

is

a

5-volt negative spike

the sawtooth sweep.

(see para. 3-6). Triggering

e2

varies the grid

circuit in

a

positive or nega-

affects

the other;

all

it

would

differ-

area

of

its

3

-3

HP 152A, 150A Service manual [en, fr]