Cushman 301 Service manual

~

---:=-

.

- _ ._- - - - _ . - .. . -. - - -

_-- - -

--

manufacturers

MODEL

301

OSCILLOSCOPE

P Y 4 A J

FAB

IO

c

E

LEe

of

precision

TEIXEIRA

s

T R

MAGAL

ON

electronic

H

A

~

M

I C

S,

instruments

N

INC.

166

Sunnyvale,

San

Lazaro

Calif.

Avenue

94086

\ .

CUSHMAN
MANUFACTURE

ELECTRONICS, INC.

TO BE FREE
FOR A PERIOD OF
FOREGOING
STATUTORY.
OR REPLACE

THIS
OF THE

operation
can be

WARRANTY

COMPANY,

This

manual

corrected

IS IN LIEU OF

THE

ANY

INSTRUMENT

HAVE

is

int

or repair. In

by the user

ONE

COMPANY,

MAY

NOT

BEEN

ended

the

to give the user a

event

with a minimum

WARRANTS
FROM

YEAR

UNDER

FOUND

APPLY

ALTERED

of

trouble,

WARRANTY

DEFECTS IN

FROM

ANY

of

lost usage time .

THE DATE OF

OTHER

THEIR

DEFECTIVE.

· TO
OR

comprehensive

study

EACH OF THE

MATERIAL

WARRANTY,

LIBERAL

INSTRUMENTS

MISUSED

the manual

carefully

INSTRUMENTS

ORIGINAL

WARRANTY,

WHICH

knowledge

Most

AND

EXPRESS,

, IN THE

of

the

instrument

OF THEIR

WORKMANSHIP

PURCHASE

. THE

IMPLIED

WILL

REPAIR

OPINION

instrument

and its

malfunctions

OR

f

•

i

,

For assistance or

problem

let
instrum
Estimates
before

CLAIM

for

carrier

Should

us

work

Your

safe

or, if

and

know.
ents

FOR

instrument

delivery

include

it

appear

Shipp

within

of

charg

is

begun

insured

informat

the

model

that

ing

instru

the one year

es for

and such

DAMAGE

should

. If the

instrument

separately, with

We

PLEASE

ion

of

and serial

the

instrume

ctions

non-warranty

be

ADVISE

warranty

work

will

IN

SHIPMENT

inspected

is

the

sincerely

to

all

users

w ill be

CUSHMAN

Dial

any kind,

numb

nt needs to be returned to the fa

or any

be

done

damaged

insurance

pledge

of

US IF WE CAN

er of the

promptly

other

other

on an a

and

tested

in any

company

our

our

precision

contact

immediate

the fa

ctory

instrument.

given to you. There will be no charge for repair on

than

transportat

service will be supplied by th e

ctual

cost basis only.

as soon as it is received. The

way

or fails to ope rate

.

and

Iullest

electron

ASSIST

ic

instruments.

YOU

ELECTRONICS,

166

San

Lazaro Avenue

Area

Code

408

- REgent 9

Sunnyvale, California

. Give full details

ctory

for service or

ion costs

cooperation

IN

ANY

after

properly

MANNER

INC.

-6760

of

the

nature

recalibrat

90

days of ownership

factory

instrument

. file a

upon

claim

of

your

ion ,

request

is insured

with

the

.

P Y 4 A J

!

ABID

TEIXEIRA

MAGALHA

FS

CONTENTS

,
,

•

t

SECTION

SECTION

.

SECTION

SECTION

SECTION

GENERAL

1.

OPERATING

2 .

2.1 General · ·

2.2 Deviation Mea surem ent s .

2.3 L

3 .

CIRCUIT D ESCRIPTION

3.1 Genera l .

3.2

3.3

3.4

3.5

MAINTENANCE

4.

4.1 Calibrat ion Adj ustme nts

4.2

5.

SCH

5.1

52

5.3

2-1 Oscilloscope Fr

3-1
3-2

4 -1 Mo del 301 Oscill oscope, L
4 -2 Mode l 301 Oscil loscope. R

5 -1

5-2

5-3

5 -4 Vertical

5

-5

DESCRIPTION

INSTRUCTIONS

ow

-Frequency Phase Compa rison .

Vertical

Amp
Horizontal
High-Vo lta ge Pow er Supply B
L

ow

-Voltage Pow er S

4. 1.1 Vertical Adju stments .

4.1.2 Verti cal Gain .

4.1.3 CRT Balance

4.1.4 Horizonta l Gain .
Typical Volt ages and W aveforms

EMATICS

Reference Designators

Abb

rev iat ions .

Schematics. Parts Lists. and Pictorials

Overa ll Block Diagram .
Horizontal

Mo

deI301(FP
High Voltage P
L

ow

Horizontal

lifier Board .

Amp

lifier Board . .

AND

PARTS'

ont

Panel

Amp

lifier Board. Block Diagram

) . . . . . . . . . .

ow

er

Voltage Power

Amp

Ampl

Suppl

Supp

lifier (A3l . . . .

ifier and Swe ep

oard

uppl

y Board

ly . . . . . . . . . . . . . . _. . .

.

..

.

LOCATIONS

ILLUSTRATIONS

eft-Sid

e Viewof Int erior

ight

-Side View of Int erior .

y .

(A4)

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

...

.

Page

1-1

2- 1

2 -1

2- 1

. 3 - 1
. 3 -1
. 3 - 1

· . 3- 3

. 3 -3

. 4 -1

· .

......

__ __

. . . 3 -2

.3-3

.... 4 - 1

4 -1

4-2
4-

4 -2

5 -1 •

5 -1

5-2

2 -1

4 -2

5-2

5-5
5-7

5 -9

5-1 2

. 4 -1

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

2

•

•

•

•

•

•

•

•

•

•

..

•

,

..

TAB

LES

1- 1

Model 301 Specif icati

4-1
4-2
4 -3

4 -4

4 -5

4

-6

Vertical

ltage

High-Vo

tow-vonace Pow er S

CRT V

Horizont al Am plifier Board. Volt age Chart . .
Hor izontal

Supply

oltag

e Chart " .

Am

plifier Board. Vo ltage Chart . _ .

Arnplilrer Bo ard W averorm s .

ons

Board Voltage C

upply Board

Volta ge Chart .

hart

.

..

. .

__

. 4 - 3

· . 4

1-1

4 -3
4

-3

4 - 3

-4

4

-4

•

•

•

•

..

•

..

..

,

...

"

SECTION

1

GENERAL

The

Model

301 Oscilloscope is designed for use

the Cushman Models CE-3 and CE-7 FM Communica-

Monitors

tions
visually examine the exact

transmitter. Any
anced
usual clipping , and
apparent so
Model

modulat

301 has an
precisely display
brated to

, The Oscilloscope enables the user to

abnormal

ion, pulses from the

that

appropriate repairs can be made . The

automatic

waveforms. Vert

show

deviation on

DESCRIPTION

modulation

conditions

other

problems

sync

anyone

with

delivered by the

such as unbal-

power

circuit

ical display is cali-

supply, un-

are immediately

to

lock

on and

of three ranges:

± 1.5, ± 5, and ± 15 kHz,

while

for routine

switches

using the

Front panel

nal

input

may also be connected to

oscilloscope can be used

ing

function

playing Lissajous patterns, etc.

permit

an external vertical sig -

internal

independently

testing, trouble

sweep

. External signals

the

horizontal input. Thus, the

of the

shooting , dis -

monitor-

Figure

2·'

Oscilloscope

Deviation Accuracy

External

External Vertical Sens

External Frequen cy Response (3 db)

Inputs

itivity

Front

Panel

Table

1-1.

Model301

1-1

± 5%full scale in three ranges:

Vertical and Horizontal

300

30

Specifications

± 1.5 kHz,

millivolts

kHz

5.0

kHz, 15 .0 kHz

for full-scale

SECTION

2

2.1

General

The

Model

ard

oscilloscope
self-explanatory
tensity

ensure a clean trace on the face

and
the display and set the

reference line on the scope

function

switch
calibrated
The scope
viation
test is

amplifiers

O9gle
ternal signals in
co ectors

s .e

_ j can then be easily

control.

horizontal

The lever

for

will

off

Separate

switches

e

Model

ep-speed

sce

ssarv to
eform
a tomatic sync
any signal ex

itude. An e

ation of sig nals

3 ge

ntercloc wise.

_a

ged

ause the

301

Oscilloscope

front-panel

. (See Figure 2-1 .) A

and

astigmatism

position

switch

is In the CAL.

switch

vertical

in ± 1.5 .

circuit

shift

frequency

external

which

being

odel

slotted

from the

directly

display

±5.

is

de-coupled

up or

.

inputs

drive the CRT are

permit

conjun

301

sweep

swit

ch and

adjust

the

displayed. The

control

ceeding

xternal-vertical-gain

301

Oscilloscope

knob

When

plug-in.

plug-in

removed

controls. most

controls

display

down

selection

ction

applied

on the rear panel of the

the

connector

are

with

graticule

position.

below

of

deviation

and ± 15 kHz of

if the

to the

with

speeds

vernier

sweep

Model

which

one division

to the

locking

pushing

.

OPERATING

Plug -In has the

of

which

focus

control.

control

and the

of

can be

speed to

is

to separate . The

are

provided

of

the CRT.

provided

respect to the zero

when

the CRT is a range

and is

transmitter

vertical

provided.

either

the

adjusted

control

; it is

301

provides

in

control permits

external

removed

shaft

the

Vertical

to

position

the CE-3

directly

deviation

displayed

or

horizontal

Separate
internal
external

normally

lock

the
incorporat
instant

peak-to-peak

by

monitor

has been dis-

knob

stand-

are

in-

to

de-

under

or ex-

input

with

audio

es

lock

vertical
turning

inward

Model

INSTRUCTIONS

2.2

ation is described in the

2.3

.

a

Deviation

Operation of the

Model

CE-3 or

Low

The

Model
tone-operated squelch devices (such as the Vibra­sender) by using the

the

Model

308

a. generate an

that has a frequency of 10 times.

times

that

of the signal

b. Set up the

c. Feed the

the HORIZ.

d. Feed the signal to be

PUT

e.

est

moving

INPUT

connector

Adjust

Lissajous

Measurements

Model

Model

-Freguency

301 can be used to

Decade Frequency

IF/Audio

correct

Monitor

connector

of the

Model

the

Monitor

patte

301

CE-7 to measure

Monitor

Phase

Oscilloscope

signal in the CE-3 or CE-7

with

which

dividing

output

of the

compared

301

output

rn on the

Oscilloscope

Manual.

Comparison

compare

in

conjunction

Divider.

ratio

through

frequency

as

100

it is to be compared .

on the

the

Model

to the VERT. IN -

Model

o

with

frequency

the phase of

follows

time

s. or

Model

Model

301 .

for the

301 .

devi-

:

1000

308

308

slow

the

with

.

to

-

• rolonged
n the face

ssib!e, Use the

lo ng the life

display

of

of

the CRT .

of a bright

the CRT.

CRT

at

Avoid

half

spot

this

brightne

or

trace

condition

ss to

may

pro

•

High

voltages

if

-

2 -I

scope
replaced
mended

seconds

In is

capacitors

and

removed

are

the

plug-in

with

the

that

the

before the

to

.

used

power

power

Model

allow

in the
must

not

switch on .

switch

301

discharge

Model

be

301

be

removed

It

turned

Oscilloscope

of

all

high-voltage

Oscillo-

is
off

recom-

for

30

Plug-

or

SECTION

3

CIRCUIT

General

its of the

s- the

e board.. the

2 the High-Voltage

c supply is fused (2

cept acle J3. in the

Figure 3-1 is th e overall
supply
(ASTIGMATISM. FOCUS . and INTENSITY) are not
shown
be
plied
nector
tion .
comes
sweep
and a vernier
more
the
amplif
the
hor izontal pos ition of the CRT trace is adjustab le wi th
the

a external signal
t e EXT. pos ition) or it can come from the 2nd I.F. and

I T.

de iation

CE-7. In

ce

5 . e ed to the FREO.-DEV .

circuits

in the interest of

either

through

when

When

from

period is selectable by a

than

vertical

ier on the High -Voltage Power Supply board to

cathod

HORIZ

olt age on the horizontal defl ect ion plate s.

input

The

iscriminator board of th e CE-3 or CE-7
ERT

INPUT

posit

nt

ered

. or is in the CAL . mode. the

itored transm

nted

ese

center line. Thus. the
sed to indicate frequency error as well as FM

and the usual

externa l or internal. The external

the

the associated sw

the

swit

the internal

control

50

milliseconds. and is synchronized with

input. A blanking signal is fed

e of the CRT to blank the return trace. The

. POS.

to

the CRT

switch

ion. the oscilloscope displays the

of

the signal bein g

addit

ion. afte r the oscilloscope trace has been

vertically

by the d

Mod

el 301 Oscilloscope are on

Vertical

front-pan

(when

by the VERT. POS.

itter

Amp

lifier

board. th e Horizon-

Low

-Voltage P

Power

/10

amp S.

monitor.

block

diagram. The

cathode-ray

simplic

ity. The CRT

el HORIZ. INPUT BNC con-

itch

ch is in the INT po

sweep

from less than 0.5 milliseconds to

control. which determines

vert

is in the INT . position ) In the

's c

isplacement

generator. The internal-

ical

def

lect ion plates can be

the VERT . IN PUT switch is in

monitored

MEASURE

enter

-frequency
of the trace from the

Model

301 Oscilloscope can

ower

Supp ly board . The

B)

at the

tube

sweep

sweep

is in the EXT. pos i-

sition

. the swe ep

four-position

through

(when

modulation

by the CE

control

Mon

itor can be

mode and the

error is rep-

Supply

plug-

power

controls

can

is ap-

switch

an

the dc

the

·3

or

while the

a ion.

vertical signal input is dc- amplified and applied

of

the vertical deflect ion plates

relay K1. I

c a

mp

ster. For

itc es. the LO freq uency is 10

ialed-in frequency.

is deenergized and its co ntacts feed the vert ical in-

• siqnal to the vertical defl

5 0 cause an

rease in the

~

_ ·er.

position 0 or 1 wh ile the 2nd ·d

_ '.- n 2 or 3. the CE-3 LO frequency is 10

than the dialed-in frequency. This

_ beam to

oencv if it

nput

lifier de

most

when

defle

wer

to the
voltage
sett ings of the CE-3 frequency selec-

upward

the 1

ct

e not for the reversing action of relay

other

vertical

from the VERT POS.

When

this

ection

def

lection

frequency

st-di

downward

of the

git frequency selector swi tch

for

through

deflection

MHz

is the case. relay

plates in such a

of the CRT trace for

monitored

igit

an increa se in signal

lower

switch

would

revers -

plate

potenti-

than

way

signal.

is in
MHz

cause

DESCRIPTION

K1. wh ich is energized in these

tions

of

swit

ch pos
plifiers is
which

1.5-

.5

3.2

Figure
Amplifier
a three-stage

cle

def
biased to
tor

circuit

position. or by

swi tch is in the EXT.
02

is var ied

tent

iometer
The vertical
gain

when
inator
for the 1
tive feedback resi
06

are shunted by
for the 1
rangel to increase the
amou
those ranges. Variable resistors R32 and R31
means for

Transistor
from
out

put

Amplifier

3.3

On this
the CRT and the
flection plates of the CRT
sweep
diagram

5-5)

ure

Assume
INT. position
position. and
input.
tially
shu nted by
This
co

nstant
generative
the regenerative
starts
Source.
regenerative

C6.
causes the regenerative
charges. Thus. a
the top plate (in the

controlled

connects

-. and 15

Vertical

5-4

board. Transistors

lecti on plates of the CRT. The base of

about +3.2
when

(R5) to move the CRT trace up or

to

produce

the signal

board

.5-kHz

.5-kHz

nt to provide the

calibrating

one of the CRT

is fed to the

board .

Horizontal

board

or an external horizo ntal

(Figure 3

that

the

output

ground

approx

lowered

-current
switch 03/04

charging

When

After

C6

itions

. The

gain

by the

different

-kHz

ranges

Amplifier

is the

differential

around

amplifier

corresponds

07

schematic

volt

the VERT. INPUT switch

voltage

position

+32

is designed to have the

full-scale

from

the

and

5-kHz

stor

s in the

appropriate

cange and R29 + R31 for the 5

the

two

is the

sync

vertical

trigger

Amplifier

are the internal

amplifiers

·2)

and the

the

HORIZ. INPUT

. the SWEEP

that

there is no sync
of

Schmitt

potentia

resistance

C6 charges to the

switch

discharges

l: therefore.

imately

demands

source

switch

linearly

. the switch

sawt

ooth

block

deviation

calibrating

into

the circuit.

Board

diagram

01

amplifier

s. by the

divider

correct vert

R3 and R4

. The bias on the base of

volts

by the VERT . POS. po-

vertical
Monitor

to a dev

deviation

emitter circuits

res

amplif

ier gain by the

ranges.

amplif

deflect

circuit

Board

to

drive

from

input.
schematic

switch

Trigger

10

kilohms

(06)

can

on hence it

turns

off.

from

. the shu nt across R12
switch

to

waveform

diagraml

particular
of the

resistances

th rough

that

drives

Monitor discrim

defle

ction

2nd

I.F. and

iation

ranges . the

istances

ical

ier. Its input

ion plates . and its

on the

sweep

the

either

Refer to the

switch

is in the 10-msec

input.

01

resistor

(R13 '

more

supply

timing

the

threshold

closes and

turn

of C6 . This sweep

combina-

vertical

range

of the

06

comprise

the

is in the INT .

when

of the CRT

Discrim-

of ± 15 kHz .

of

05

(R30

deflection

provide

Horizontal

generator

horizontal

the

diagram

is in the

With

no

/02

is essen-

R12 is

plus

current

turns off. When

constant

off

is

than

to keep re-

capacitor

level of the

discharges

. and C6 re-

generated

am ­switch.
for the

Vertical

vert

01

is

ina -

the

down

proper

nega-

and

+ R32

-kHz
right

for

come

for

de-

internal

block

(Fig -

sync

R39).

the

C6

-current

again

i-

.

a

s

at

3- 1

waveform
half

hor izontal
flection
amplifier
age adjustable by

The
turned to
a

portion_pf

pac

itor
changes the
the

of a

is Jed

different

deflection

through

emitter follower

ial amplifier (Q9i Q11) to one of the

plates . The othe r

horizontal

plate is fed by the other half of the

(Q1O/Q12). the input to whi ch is a dc volt-

bottom

through

timing

HORIZ

plate

ground

the

potential

effective

period . The

POS potentiometer R7

of timing capaci tor C6 is

as is conventiona l. but instead. is fed

emitter

from the top

fol

low

ers Q7 and Q8 . This

plate

capacitan ce of C6 and therefore

amount

by

which

Q7 and one

de-

differential

not

re-

of the ca-

the

effective

capacitance is changed is controlled by the SWEEP

vernier

determined
by the SWEEP switch .
SWEEP -vernier
the

from the

pot

entiometer

not

black

SWEEP sw

Now

assume that a sync signal is being received

vertical-deflecti

. R6. Thu s. the

only

by the tim ing

but

control

(the red knob

itch)

on

sweep

capacitor

also by the

setting

concentric with

input

of the CRT. This sync

period is

selected

of the

signal is
Schmitt
posit
R9. and CR1. The

ive tr

converted

Trigger

igger

to a

Q1/ Q2. and is

pulses by the

output
charges C9 to a pos itive
biases CR5 .
R39

from

ative

sw

pulse

from

stays

off
threshold
discharges. and cannot
a

new
sync circuit. Thu s. the
vertical

When
tion. the
switch
ternal
is

sawtooth

adjustable

amount

thus

the regenerative

itch

can

now

the

trigger

until

timing

level

of

sweep

until a trigger

input.

the

HORIZ

junction

circuit

is

grounded

. The

by

potentiometer.

of

negat

ive

removing

be

circ

capacitor

the

switch. When

start

sweep

INPUT

of R12 and CR5 in the regenerative

gain

feedback

rectangular

further

circuit

of the

cons

Schmitt

voltage ; this

shunt

switch

turned

uit. The

resistors

circuit.

off

only

regenerative switch

C6 ch arges to the

this

charging

again

pulse is received

is

synchronized

switch

to

of the

is in the EXT. posi-

stop

generation

differential

R38. wh

in the

output

waveshape

converted to

isting

of C2.

Trigger also

voltage

R13 and

The regener-

by a

positive

happens

to

produce
from
with

of the in-

amplifier

ich varies the

stage .

by

back-

. C6

the
the

( XT

cr

0;-

'~ JV

(' nd : F

i:

s :~

GND r ROM 1\ 1 8 2 n d

DI GIT

8

v , 1\,:. ...

OR

12v

SWITCHES

r----------------------l

---+

L

___

EJ

TRIGGE R

CIRCUIT

ITCJ

0

"': R I

ZO

~'r :"~

___

----

~-----------------,

I

I

I

z v z

I
I
I

I

I

I

I
I

I

I

I

__

L

I

I

I

I

.¥'

':' V ;l .. t: ::: q BOARD I

I s cc- J

(' ~

1" CC- l l _" OR' Z

: " ,:

- -

______

_

R O -:"

----

~r

.: =-

:.:.

1'20 v

-=

1:

.

.....

______

AMPL lf

l(~

'o( R T ICA L

.o.~PllF I£

ll.M P Lr F I

~

------

IVER T POS

H

ORIZ.

.o.MPL

HQ RI Z

AM PL

pasI

V(

R T

I

I

I

A

I

I

I
I
I
I

I
I
I

B

I

J

8 0 AQ :

R

A

,--

ICA

L

(~

B

--

~

I

.-:

..J

§]

I

I

I

I

I

I

I

I

I

I
I

I

I

I

r -"

7'G

"-=-

v

I PYrR SUPPL Y S

I

I

I

I

L

OL

8 LA NK:'\jG

AM

PLI

_______

FI ER

L+:

r-r

T AGE- -,

OAR

D

-.J

r -

co"

R

I

R( v(RSING

I

......

?

I

I

L

__

I

I

I
I

I

vO

SUPP

~( L :';

?~,

_____

- l

LT AGE

LY BOA RD I

""""

,

J

I

I

I

I

I

-g

Iv

.

-

...

Figure 3-1

Overall Block

Diagram

High

3.4

ho

n In the sche

across the high -vo ltage secondary of

ts

IS

C 1.

across C2 is redu ced by the regulator circuit con-

, s

_ of R1. R2. R3. and V 1 to a regulated

'so,

-1200 volt

• to the grid of the CRT. and also across the

e-divider

-

2.

potential on the

SITY control. wh ich d

, E

'as

on the grid (pin 2)

addition.

rizontal

...

aug capacitor C4 to the cathode of the CRT.

oH he

beam

-Voltage

board fur nishes - 1200 volts for the CRT. As

applied

to

CR1. CR2 . and C2. The approxi mately -2 100

chain consisting of INTENSITY cont rol

Rll

. FOCUS control CH

during

amplifier

Power

mat

ic diagra m. Figure 5 -2 . the

the voltage

output

is applied th

cathode

retrace a

is

inverted

Supply Board

-doub

ler rectifier consisting

roug

-Rl

. R12 . and

of the CRT is set by the

eterm

ines the negative

with

respect to the

negative

by

Oland

f OLLOWER OUTPUT

pulse

BL ANKINGl

EMITTE R

OS

This board (Fi

920

transform

-1200

h R9. lOO k

from

volt s.

volt

R13

cathode

the

appl ied

cutt

er

ing

horizontal amplifier on the Horizontal Amp lifier board.
and to th e
amplifier on the High-Voltage Powe r
ac

voltaqe

of

Tl
plied to bridge rectifier CR1
320-vo

the em

­CR5. and CR6. to the board conn

.

:

Resisto rs R3 and R5.

l

ector
the Vertical
changing the values of the load res

compensat
sistors and to adjust the electri cal
beam to mid -scale . The fun
plained in

r----------------------------l.-

Low

-Voltage

ASTIGMATISM

of

245

on the Hi

lt o

utp

ut of the bridge r

itter

-follower

load resistors of vertical

Amplifier

e fo r any differen ce in gain of the

Section

Power

gur

e 5-3) furn ishes

volt

s rms from one of the secondaries

gh-

Voltage

regulator. consisting

board. Potent

3.1.

Supply Board

potentiometer

Pow

er Supply boa rd is ap -

throu

ector

tog

ether with

amplifiers 05

ction

gh CR4. The positive

ect

.

of relay K1 is ex-

240

volts to the

and b

lanking

Supp

ly boa rd. An

ifier is fed through

of

01

. R2.

R4. are the col-

and

06

on

iometer

istances

displacem

R4

perm

slightly

two

tran-

ent of the

BL ANKING

its

to

S.

' ...._·1

CO,.S TANT

CU~~EN

T

SO~

~C

E

0 6

,--

CRS

I .....

I

......

REGEN

SWITC H

0

R I 2

3/

0 4

..1£

SCHM I T T

c

__

T RIGGER

>-.L~...-I

QI / 0 2

RI3

~ 3 9

1:

....

B

_I

~

.7 /~6

1

'"

J

[Q}] ISWEEP I

SWI TCH

~

SW 3

fEEOBA

f OLL OwE R

..-j

~

C5

CK

EMI TT ER I

OB

COUPLI NG

E' " TTER

f OLLo wER

0 7

.....

'-----t.~

.. .

ISWEEP I
VERNI ER

CH-R 6

-=

II

I

[@]

)

~

" I

~:

1

I SW4

I

~h

7

2

1

~?

~~

...------,

HOR I Z

AM: L

1--_--1~

09

/0

11

~H

HOR , Z

AM PL .

B

0 10 / 012

ORIZ

GAIN

R38

SWEEP

OUTPUT

TO HORtZ

OEf L PLA TES

I

Figure

3-2

Horizontal

Amplifier

3-3

Board.

Block Diagram

""""

.......

ration

~

:l

~"-""'

'V'''

.

Adjustment

six

internal

Controls for

n in Figures

adjustments

these

4-1

e cept the horizontal gain

t e

Model

301 plugged

· 0 and

can be reached

operating

. The

by

removing the

controls

CE-7 cover. as described in the
of

t e

Monitor
quired is an
frequency
stated, the
dures are on the

4,1,1

Vertical

adjustments

cal

amplif

ier balance should be checked as

a. Place the

posit

ion .

b. Set the

Manual.

unmodulated

covered by the

controls

Model

mentio

301

Amplifier

of the vertical

Monitor

front-panel

The

only

transmitter

Monitor

ned in the

Oscilloscope.

Balance.

deviation

function

VERT. POS

pos it ion.

c. Set the

posit

ion and note the

-panel range

swit

position

front

CRT.

d.

Switch
sition
using the
FIgure

to the ± 1

.5-kHz

range and

of the trace to the same point noted above ,

vertical_ ampl

ifier

4-1).

SECTION

MAINTENANCE

in the

adjustments

and

into

maintenance

test

. Unless

Before

switch

ch to the ± 15
. of the trace on the

balance

Model

301

are Io-

4-2

. The adjust-

adjustment)

the CE-3 or CE-7

.shown in Figure
left-hand

CE-3 or

section

equipment

operating

on any

otherwise

following

mak

proce -

ing any

ranges. the verti-

follows

:

in the CAL.

control

to mid -

-kHz

adjust

the po-

control

are

re-

(see

4

4.1.2

Vertical

'a. " Dial-in " the

used for

b. In the CAL. pos

switch.

scale reading on

c. Set the

± 1.5 kHz and adjust

trace is on the '

d. Set the

DEV.

just

FREQUENCY error

With

e.

offset
low
trace should
justment
ometer

f. Repeat step e. on the

offsetting

Ad

just

g. Repeat step e. on the ± 1.5

by
kHz.

h. Recheck the vert ical

by repeating steps a.

Gain.

frequency

the

test.

ition

adjust the CA L.

the

FREQUENCY

front-panel

'0"

reference line .

Monitor

MEAS

it " right on

. pos

function

ition

frequency

meter

the

deviation

range switch

the " dialed·in "

from

the FCC assigned

shift

up and

is required, use the ±

; the n recheck

the "dia

the

±5-kHz

offsetting

Adjust

the ± 1

the

led-in" frequency

the " dialed-i

.5-kHz

dev

the

. Key the

frequency

±5-kHz

potentiometer

amplifier

through

of the

of

the

control

for a zero or

meter

iation

VERT. POS.

switch

transmitter

"on

range.

frequency

down

transm

itter

·kHz

n"

potent

iometer

balance

d. of

transmitter

Monitor

being

funct

ion

mid-

.

range

control

to the

switch

so the

FREQ.-

and ad-

the ± 1.5

-kHz

set to ± 15 kHz.

15 kHz

high

and

. The scope

by 15 kHz.. If ad-

15-kHz

frequency

deviation

potenti-

.

range by

by 5 kHz .

if

necessary.

deviation

frequency

range

by 1.0

if necessary.

adjustment

Section

4.1 .1.

to

:::. :-=

·L~~o~

Figure

±5

C.RT.

BALANCE

kHz

).

:.

·

VERT

4-1.

Model

301

Oscilloscope.

! 1.5 kHz

.( -1

Left-Side

View

. AMP

BALANCE

of

Interior

tiS

kHz