Simpson Electric 479 Operator's Manual

OPERATOR’S

MANUAL

MODEL

479

FM-TV

SIGNAL

GENERATOR

SIMPSON

ELECTRIC

COMPANY

5200W.ICinzie

St.,

Chicago

44,

Illinois,

ES

9-1121

In

Canadz.

Bach-Simpson.

Ltd.,

London,

Ontario

'

Simpson

Electrk

Co.,

Chkogo

44,

IIInos

1

A.

M.

GENERATOR

400

r,

AUDIO

GENERATOR

F.M.

GENERATOR

CRYSTAL

CALLBRATOR

FIG.

1.

THE

MODEL

479

TV-FM

SIGNAL

GENERATOR

-z

MODEL

.479+TV

-FM

SIGNAL

GEHERATOD

Y

L

,uLjc

O

‘14p

frMP

&L

7-

MODEL

479

FM-TV

SIGNAL

GENERATOR

The

Simpson

Model

479

Signal

Generator

has

been

designed

carefully

to

supply

all

the

necessary

signal

sources

for

the

proper

alignment

and

servicing

of

TV

and

FM

receivers.

For

your

convenience,

markings

on

the

FM

Generator

tuning

dial

allow

you

to

tuneitaccording

to

the

frequency

which

you

require,

or

according

to

television

chan

nel

number

for

RF

signals

through

both

VHF

and

UHF

ranges.

There

are

two

separate

tunable

oscillator

sections.

Each

oscillator

section

is

pro

vided

with

a

large,

precision

vernier

dial

having

a

20:1

knob-to-pointer

ratio

and

a

1000

division

logging

scale.

They

are

easy

to

read and

easy

to

settoany

exact

fre

quency

within

the

range

of

the

generator.

Everything

possible

has

been

done

to

make

the

Model

479

the

most

accurate,

flex

ible

and

convenient

instrument

available.

Each

part

of

this

instrument

has

been

con

sidered

carefully

for

long

life

and

stability.

Many

of

the

vital

components

are

manu

factured

under

rigid

supervision

within

our

own

plants

in

order

to

insure

lasting

accur

acy

and

many

years

of

uninterrupted

service.

DESCRIPTION

The

Model

479

is

arranged

in

two

major

sections

as

shown

in

figure

1.

The

left

hand

section

contains

a

crystal

calibrator,a400

cycle

audio

oscillator,

and

a

three-

range

r-f

generator

which

can

be

amplitude

modulated

with

the

output

of

the

400

cycle

oscillator.

The

desired

type

of

signal

is

selected

by

the

SIGNAL

switch

left.

The

SIGNAL

switch

has

five

positions,

named OFF,

tJNMOD.

R.F.,

CAL.,

MOD.

R.F.,

and

AUDIO.

When

the

switchisin

the

OFF

position,

the

entire

A.M.

Generator

is

inoperative.

When

the

switchisin

the

UNMOD.

R.F.

position,

anunmodulated

r-f

signal

is

available

through

the

OUTPUT

jack

and

cable.

The

amplitude

is

controlled

with

the

SIGNAL

ATTENUATORS,

with

both

fine

and

coarse

adjustments

center

and

right.

When

the

switch

isinthe

CAL.

position,

the

outputofa

5.0

mc.

crystal

oscillatorismixed

with

the

output

of

the

R.F.

Generator

to

produce

a

"beat"

according

to

the

information

in

table

1.

The

beat

pattern

can

be

observed

on

an

oscilloscope

connected

with

the

VERT.

AMPL.

and

HORIZ.

AMPL.

cables.

By

using

table1and

the

oscilloscope,anyfrequency

within

the

range

of

the

instrument

can

be

produced

quickly

and

precisely.

When

the

switch

is

in

the

MOD.

R.

F.

position,

the r-f

signal

is

amplitude

modulated

30%

witha400

cycle

audio

frequency

and

the

modulated

signal

is

available

through

the

OUTPUT

jack

and

cable.

The

amplitude

is

controlled

by

the

SIGNAL

ATTENUATORS.

When

the

switch

is

in

the

AUDIO

position,

a

400

cycle

signalisavailable

through

the

OUTPUT

jack

and

cable.

The

amplitude

is

controlled

by

the

SIGNAL

ATTENUATORS.

A

potentiometer

andafive-position

switch

together

comprise

the

SIGNAL

ATTEN

UATORS.

The

switch,

at

the

right,

is

the

coarse

amplitude

selector

for

the

output

of

the

a-rn

generator,

and

the

potentiometer

acts

asafine

adjustment

on

amplitude.

The

A.M.

GENERATOR

RANGE

switch,

located

just

below

the

center

of

the

dial,

selects

each

of

the

three

bands

of

radio

frequencies.

The

tuning

knob

varies

the

fre

quency

throughout

each

band.

Band

A.

Fundamental

3.3

to

7.8

mc.

Second

harmonic

6.6

to

15.6

mc.

Band

B.

Fundamental

15to38

mc.

Second

harmonic

30

to

76

mc.

Band

C.

Fundamental

75

to

125

mc.

Second

harmonic

150

to

250

mc.

-3-

The

POWER

switch

lower

enter

controls

the

power

inputtoboth

sectionsofthe

Model

479.

When

the

switchisin

the

OFF

position

the

entire

instrumentisturned

off.

In

the

STAND

BY

position,

all

the

tube

filaments

are

turned

on

but

no

plate

voltage

is

applied.

In the

OPERATE

position,

plate

voltageisapplied.

The

green

light

is

on

for

both

STAND

BY

and

OPERATE

positions

of

the

switch,

and

the

red

light

is

on

for

the

OPERATE

position

only.

In

the

center

of

the

Model

479

there

are

three

jacks

which

are

labelled,

from

top

to

bottom,

HORIZ.

AMPL.,

VERT.

AMPL.,

and

SIGNAL

INPUT.

A

cable

from

the

HORIZ.

AMPL.

jack

should

be

connectedtothe

horizontal

input

terminal

with

the

red

insulated

clip

and

ground

with

the

black

insulated

clip

of

the

oscilloscope

used

in

con

junction

with

the

Model

479.

Set

the

function

switch

of

the

oscilloscopetoutilize

this

signal

for

the

horizontal

sweep.

The

switch

position

will

usuallybenamed

"horizontal

amplifier

or

"horizontal

input"

on

the

oscilloscope.

This connection

is

important

be

causeitoffers

the

operator

his

most

convenient

source

of

60

cycle

sine

wave

sweep

voltage

which

may

be

phase

adjusted

relativetothe

f-rn

sweep

voltage

with

the

PHASING

control

on

the

Model

479.

There

is

more

information

on

this in

the

discussion

of

the

PHASING

control.

A

cable

from

the

VERT.

AMPL.

is

usedtoconnect

the

source

of

the

response

patterntothe

vertical

input

terminal

with

the

red

insulated

clip

and

ground

with

the

black

insulated

clip

of

the

oscilloscope.

A

cable

from

the

SIGNAL

INPUT

jackisused

to

connect

the

signal

outputofthe

amplifier

under

test

back

into

the

Model

479.

This

signal

willbefed

through

the

SIGNAL

switchto

the

VERT.AMPL.

jack

when

the

switchisin

the

OFF,

UNMOD.

R.F.,

MOD.

R.F.,

or

AUDIO

position.

The

right

hand

sectionofthe

Model

479

contains

a

frequency

modulated

signal

gen-

erator,a

140

rnc.fixedfrequencyoscillator,a

mixer,

and

phasing

and

blanking

circuits.

The

output

of

the

f-rn

signal

generator

is

connected

throughanattenuatortothe

OUTPUT

jack.

The

OUTPUT

jack

serves

both

the

a-mandthe

f-rn

signal

generators

so

that

only

one

connection

need

be

made

to

the

input

of

the

receiver.

The

F.M.

GENERATOR

RANGE

switch

below

the

centerofthe

dial

has

three

posi

tions.

In

the

OFF

position,

the

f-rn

generator

sectionofthe

Model

479

is

inoperative.

In

theAposition,

both

the

140

mc.

fixed

frequency

oscillator

and

the

tunable

f-rn

oscil

lator

are

operating;

one

output

frequency

from

the

mixer

is

the

difference

between

these

two

frequencies.

The

fundamental

range

of

the

beat

frequencies

is.2

to

120

mc.

The

locations

for

RF

signals

for

television

channels2through6are

marked

in

areas

be

low

the

corresponding

frequencies.

In

the

B

position,

the

switch

turns

off

the

140

mc.

fixed

frequency

oscillator,

and

the

output

from

the

variable

frequency

oscillator

is

available

at

the

output.

The

fundamental

range

of

the

B

band

is

140to260

mc, The

locations

for

RF

signals

for

channels

7

through

13,

which

use

fundamentals

of

the

B

band,

are

marked

in

areas

below

the

corresponding

frequencies.

The

locations

of

B

band

frequencies

which

will

have

harmonics

required

for

RF

signals

for

channels

14

through

83

are

marked

ingroups

above

theB

band.

Channels

14

through

21

use

second

.jiarmonics,22

through65use

third

harmonics,

and66

through83

use

fourth

harmonics.

The

tuning

knobinthe

dial

serves

to

select

any

frequency

within

the

range

indicated

on

the

arcs

of

the

CENTER

FREQUENCY

dial.

The

F.

M.

ATTENUATORS

are two

controls

which

act

as

coarse

and

fine

adjust

ment.

A

5-position

switch

provides

coarse

control

on

attenuation

andacontinuously

variable

potentiometer

provides

the

fine

control.

The

F.M.

SWEEP

control

regulates

the

amount

of

frequency

variation

due

to

modulation.

The

center

frequency

of

the

fundamental

can

be

swept

through

a

band

width

of

zero

to

15

megacycles.

Harmonics

can

be

swept

through

multiples

of

this

band

width,

correspondingtothe

harmonic

order.

The

rateatwhich

center

frequen

cies

are

swept

through

any

selected

range

and

back

is

the

modulation

frequency

of

60

cycles.

The

PHASING

controlisa

phase

adjusteronthe

60 cycle

sine

wave

signal

furnished

to

the

HORIZ.

AMPL.

jack.

It

is

to

be

used

to

adjust

the

phase

relations

between

the

oscilloscope

sweep

and

the60cycle

sweep

modulationon

the

carrier.

With

the

PHASING

controlitis

possible

to

superimposethe

response

patternonthe

forward

trace

over

the

pattern

on

the

return

trace.

The

BLANKING

control

hasapotentiometer

andaswitch

on

the

same

shaft.

The

switch

is

actuated

at

the

full

counter-clockwise

knob

position.

When

the

knob

is

in

the

OFF

position,

no

blanking

occurs

and

the

F.M.

Generator

oscillates

continuously,

When

the

knobisrotated

towardits

numbered

range,the

switch

actuates

and

applies

a

60

cycle

voltagetothe

f-rn

oscillator

gridtoblock

out

oscillations

during

its

negative

half

cycles.

Turning

the

BLANKING

control

through

its

numbered

range

changes

the

phasing

of

the

blocking

voltage

with

respect

to

the

horizontal

sweep

to

the

oscilloscope.

Thus

either

the

forward

or

the

return

trace

can

coincide

with

the

periodofoscillation

and

the

alter

nate

trace

can

coincide

with

the

time

during

which

the

oscillator

is

turned

off.

On

the

oscilloscope,

the

operator

will

seeasingle

response

curve

withabase

line

through

it.

Four

cables

are

furnished

for

connecting

the

Model

479

toareceiver

and

to

an

os

cilloscope.

One

cable

fitsinthe

OUTPUT

jack

and

has

a

termination

box

at

the

other

end

which

may

be

adapted

quickly

to

the

receiver

input

impedance

with

an

optional

2000

rnmf

capacitor

in

series

for

use

on

circuits

havingad-c

component.

Most

receiver

inputs

can

be

matched

without

using

any

external

resistorsorcapacitors.

See

table

2

and

figure

14.

The

other

three

cables

are

identical

and

are

to

be

used

in

the

HORIZ.

AMPL.,

VERT.

AMPL.,

AND

SIGNAL

INPUT

jacks.Apairofclipsatthe

other

end

of

each

cable

are

to

be

used

for

receiver

output

and

oscilloscope

connections.

The

red

insulated

clips

connect

the

"hot

leads

and

the

black

insulated

clips

are

for

ground

con

nections.

During

normal

alignment

procedure,

the

signalissent

outofthe

OUTPUT

jack,

to

the

receiveir

under

test,

returned

to

the

Model

47.9

through

the

SIGNAL

INPUT

jack,

through

the

SIGNAL

switch

many

position

except

CAL.,

and

out

the

VERT.

AMPL.

jack

to

the

oscilloscope.

This

arrangementwas

designed

to

simplifythe

alignment

operation

byinternalswitchingof

the

oscilloscope

input.

Whenthe

SIGNAL

SWITCH

isinthe

CAL.

position,

the

signal

fed

to

the

VERT.

AMPL.

jack

is

the

audio

beat

frequency

produced

by

the

a-m

generator

and

the

crystal

calibrator

near

any

of

the

calibration

points

listed

4’r,

+h1’

CALIBRATION

PROCEDURE

FOR

DETERMINING

TUNABLE

FREQUENCIES

WITH

CRYSTAL

ACCURACY

The

Model

479

has

two

precision

vernier

dials;

one

is

used

for

the

a-rn

generator

and

the

other

for the

f-rn

generator.

The

a-mgenerator

can

be

used

asamarker

gen

erator

for

both

FM

and

TV

alignment.Itneeds

to

be

extremely

accurate

to

adjust

FM

and

TV

receivers

properly.

The

basic

accuracy

is

better

than

1%

output

frequency

against

dial

indications,

but

it

needs

to

be

even

more

accurate

for

alignment.

For

this

reason,

the

Model

479

is

provided

withacrystal

oscillator

standard having an

accuracy

of

.05%

or

better,

Itisby

use

of

this

standard

and

the

logging

scale

of

the

a-rn

gen

erator

that

frequencies

with

crystal

accuracy

may

be

establishedatany

point

in

the

range

of

the

a-rn

generator.

To

prepare

the

Model

479

for

calibration,

turn

the

POWER

switchtoOPERATE;

SIGNAL

switch

to

CAL.;

SIGNAL

ATTENUATORS

to

a

low

setting;

and

the

A.M.

GEN

ERATOR

RANGE

switch

to

A,

B,

or

C

depending

on

the

frequency

to

be

established.

Connect

the

VERT.

AMPL.

cable

to

the

vertical

inputofthe

oscilloscope.

Connect

the

HORIZ.

AMPL.

cable

to

the

horizontal

inputofthe

oscilloscope

if

a60

cycle

sine

wave

sweep

is

desired

calibration

beats

can

be

observed

with

eithera60

cycle

sweep

or

linear

sweep

in

the

osci]oscope.

With

horizontal

deflectiononthe

oscilloscope

due

to

-5-

either

the

internal

sweep

or

the

60

cycle

sine

wave

sweep,

advance

the

vertical

arnpli

fier

gain

of

the

oscilloscope

and

slowly

rotate

the

a-rn

generator

tuning

knob

while

observing

the

oscilloscope

screen.

At

various

tuning

points

a

pattern

will

appear

on

the

oscilloscope

screen.

Rotate

the

dial

slowly

through

the

area

in

which

a

pattern

can

be

seen.

Firstahigh

frequency

appears,

then

as

the

knob

is

rotated

slowly,

note

that

the

frequency

reduces

to

zero,thenincreasesto

a

high

frequencyagain

and

disappears.

The

patterns

are

the

results

of

beat

frequencies

developed

between

the

a-rn

oscillator

and

the

5.0

mc

crystal

oscillator.

The

point

at

which

the

pattern

reduces

to

zero

frequency

is

known

as

zero

beat

and

is

the

point

at

which

the

two

oscillators

are

in

step.

The

zero

beat

pointisidentified

easily

by

the

fact

that

the

slightest

movement

of

the

dial

in

either

direction

will

cause

the

pattern

to

increase

in

height

and

in

frequency.

At

zero

beat

the

pattern

is,

essen

tially,astraight

line.

At

the

higher

frequencies

it

is

sometimes

difficulttobring

the

pattern

down

to

exact

zero

beat,

but

thisisnot

important

so

long

as

itisbrought

down

to

within

two

or

three

hundred

cycles.

This

shows

three

to

five

cycles

ona60

cycle

sweep.

Note

that

some

points

on

the

dial

will

produce

much

larger

patterns

than

others.

This

is

due

to

the

order

of

harmonics

of

the

two

oscillators

producing

the

beat

pattern.

The

lowei

harmonics

resultina

stronger

beat

pattern.

Some

of

the

weaker

patterns

may

require

a

higher

settingofthe

vertical

gain

controlofthe

oscilloscope.

TabLe

1

has

been

developed

to

assist

the

operator

in

identifying

the

frequencies

where

beat

patterns

occur

and

the

oscillator

harmonics

which

produce

them.

The

frequencies

preceded

by an

asterisk

4

will

produce

the

stronger

patterns

and

should

be

used

wherever

possible.

FIG.

2.

THE

MODEL

479

AM-FM

LOGGING

DIAL

Figure

2

is

an

illustrationofthe

logging

arcs

as

they

are

used

in

both

a-rn

and

f-rn

generator

dials.

The

upper

arc

of

each

dial

is

divided

into

10

equal

divisions

marked

from

0

to

100.

On

the

knob

shaftisanother

dial

marked

in

100

equal

divisions.

The

gear.

ratio

between

the

knob

shaft

and

the

pointerissuch

that

one

revolution

of

the

knob

shaft

moves

the

pointer

through

one

of

its

ten

divisions.

Thus

each

divisionofthe

logging

scale

is

effectively

divided

into

100

parts

and

the

entire

arc

into

1000

parts.

The

minor

divisions

may

be

divided

visually

for

further

increasing

the

number

of

logging

points

and

the

resulting

accuracy

of

calibration

information.

For

example,

the

reading

on

the

logging

scaleinfigure2is

22.5.

The

main

pointer

shows

that

the

setting

is

20

plus

some

additional

amount,

and

the

dial

on

the

knob

shaft

shows

that

the

additional

amount

is

2.5.

If

the

knob

were

turned

slightly

counterclockwisesothe

dial

setting

were

half

way

between

2.5

and

2.6,

it

could

be

read

as

2.55

and

the

indicated

setting

would

be

22.55

divisions.

Take

advantage

of

the

visual

division

of

these

marked

points

and

effectively

increase

the

accuracy

to

2000

or

more

scale

divisions.

-6-

TABLE

I

-

CRYSTAL

CALIBRATING

POINTS

BAND

A

BAND

B

BAND

C

2ND

VAR.

XTL.

2ND

VAR.

XTL.

2ND

VAR.

XTL.

FUNDAMENTAL

HARMONIC

OSC.

FUNDAMENTAL

HARMONIC

OSC.

FUNDAMENTAL

HARMONIC

OSC.

MEDACYCLES

MEGACYCLES

HARM.

MEGACYCLES

HARM.

MEGACYCLES

HARM.

*333

*7

3

2

*1500

‘30.00

1

3

‘70.0

‘140

1

14

3.46

6.92

13

9

15.83

31.66

6

19

72.5

145

2

29

3.50

7.00

10

7

16.00

32.00

5

16

‘750

‘150

1

15

3.57

7.14

7

5

16.25

32.50

4

13

77.5

155

2

31

3.64

7.28

11

8

‘16.67

‘33.34

3

10

‘80.0

‘160

1

16

*375

*7.50

4

3

17.00

34.00

5

17

82.5

165

2

33

3.89

7.78

9

7

‘17.50 ‘35.00

2

7

‘85.0

‘170

1

17

‘4.00

‘8.00

5

4

18.00

36.00

5

18

87.5

175

2

35

4.09

8.18

11

9

‘18.33

‘36.66

3

11

‘90.0

‘180

1

18

*4

17

‘8.34

6

5

18.75

37.50

4

15

92.5

185

2

37

4.29

8.58

7

6

19.00

38.00

5

19

‘95.0

‘190

1

19

4.38

8.76

8

7

‘20.00

‘40.00

1

4

97.5

195

2

39

‘4.44

‘8.88

9 8

21.00

42.00

5

21

‘100.0

‘200

1

20

4.50 9.00

10

9

21.25

42.50

4

17

102.5

205

2

41

4.55

9.10

11

10

‘21.67

‘43.34

3

13

‘105.0

‘210

1

21

4.58

9.17

12 11

22.00 44.00

5

22

107,5

215

2

43

‘5.00

‘10.00

1

‘22.50

‘45.00

2 9

‘110.0

‘220

1

22

5.63

11.26

8

9

23.00

46.00

5

23

112.5

225

2

45

‘5.71

‘11.42

7

8

‘23,33

‘46.66

3

14

‘115.0

‘230

1

23

5.83

11.66

6

7

23.75 47.50

4

19

117.5

235

2

47

6.00

12.00

5 6

24.00

48.00

5

24

‘120.0

‘240

1

24

‘6.25

‘12.50

4

S

‘25.00

‘50.00

1

5

122.5

245

2 49

6.43

12.86

7

9

26.25

52.50

4

21

‘125.0

‘250

1

25

‘6.67

‘13.34

3

4

26.67

53.34

3

16

6.87

13.74

8

11

‘27.50

‘55.00

2

11

‘7.00

‘14.00

5

7

28.33

56.66

3

17

7.14

14.28

7

10

28.75

57.50

4

23

7.22

14.44

9

13

‘30.00 ‘60.00

1

6

‘7.50

‘15.00

2 3

31.67

63.34

3

19

7.72

15.44

11

17

‘32.50

33.33

‘35.00

36.67

‘37.50

‘65.00

66.66

‘70.00

73.34

‘75.00

2 3

1 3

2

13 20

7 22 15

ASTEHISK

‘

INDICATES

ThE

SThONGEB

CALIBRATION

POINTS.

DETERMINING

AN

EXACT

FREQUENCY

There

are

two

methods

by

which

a

given

frequency

setting

may

be

obtained.

They

are

somewhat

similar

but

one

is

simpler

while

the

other

yields

more

accurate

resuits.

The

first

method

is

the

simpler

and,

with

practice,

can

produce

acceptable

results

for

most

purposes.

The

process

consists

of

first

determining

the

number

of

logging

scale

divisions

which

correspond

toaone

megacycle

frequency

difference

which

in-

cludes,

the

desired

frequency;

second,

mathematically

figuring

the

number

of

logging

scale

divisions

the

desired

frequency

is

away

from

a

crystal

check

point

see

table

1;

third,

turning

to

the

crystal

point

and

observing

its

logging

scale

reading;

and

fourth,

adding

or

subtracting

the

determined

number

of

scale

divisions

to

or

from

the

reading

at

the

crystal

check

point.

When

the

logging

scale

is

settothe

reading

obtainedinthe

fourth

step,

the

oscillator

will

be

tuned

to

the

desired

frequency.

A

step-by-step

example

of

the

first

method

follows.

Assume

that

a

frequency

of

20.75

mc.

is

desired

in

the

A.M.

Generator.

Note

that

table

1

showsastrong

cali

bration

check

point

at

20

mc.

Set

the

A.M.

GENERATOR

RANGE

switch

to

B,

the

SIGNAL

switch

to

CAL.,

and

the

SIGNAL

ATTENUATORS

low

to

see

the

zero

beat

in

dications

on an

oscilloscope

with

the

VERT.

AMPL.

and

HORIZ.

AMPL.

cables

con

nected.

Have

the

POWER

switch

in

either

STAND

BY

or

OPERATE

position

for

at

least

15

minutes

before

beginning

the

calibrationtoallow

the

Model

479

to

warm

up,

and

set

it

in the

OPERATE

position

to

calibrate.

1.

Observe

the

tuning

arcofrange

Bfrom

apositiondirectlyinfront

of

the

pointer

to

avoid

parallax

error

and

set

the

pointer

over

the

20

megacycle

mark

on

the

dial..

Record

the

logging

scale

reading

for

this

setting.

Ona

sample

unit

the

setting

was

36.0

use

your

readings,

since

there

willbevariation

from

one

unit

to

another

which

does

not

affect the

accuracy

in

any

way.

Set

the

pointer

exactly

over

the 21

megacycle

mark

on

the

dial.

Again

record

the

logging

scale

reading.

The

sample

unit

read

40.45

for

this

setting.

Subtract

the

first

reading

from

the

second

to

obtain

the

number

of

scale

div

isions

which

correspond

to

one

megacycle.

40.45-36.0

is

4.45

divisions.

2.

Determine

the

frequency

difference,inmegacycles,

between

the

desired

fre

quency

andacheck

point

table

I;

then

multiply

this

differencebythe

resultofstep

i

above.

In

the

example,

the

desired

frequency

of

20.75

mc.

is

.75

mc.

away

from

the

strong

calibration

check

point

at

20

mc.

The

result

of

step1shows

thatin

this

area

of

the

sample

unit,

a

change

of

4.45

scale

divisions

corresponds

toachange

of

one

mega

cycle.

Multiply

.75x4.45

to

get

3.33

divisions.

3.

With

the aidofthe

oscilloscope,

tune

the

generator

to

its

zero

beat

position

for

the

chosen

calibration

check

point

and

record

the

logging

scale

setting

for

this

position.

In

the

example,

the

sample

unit

was

tuned

to

20

megacycles

and

the

logging

scale

read

36.2

divisions.

4.

Add

or

subtract

the,

resultsofsteps2and

3.

Addifthe

check

point

frequency

is

lower

than

the

desired

frequency,

or

subtractif

the

check

point

frequency

is

the

higher.

This

sum

or

difference

is

the

logging

scale

settingtouse

for

the

desired

frequency.

In

the

example,

add

because

the

check

point

is

below

20.75

mc.

3.33

to

36.2toobtain

39.53

divisions.

Note

that

the

logging

scale

readings

are

forasample

unit

only.

Do

not

use

these

readings.

Obtain

the

logging

scale

readings

for

your

Model

479

and

use

them

in a

sim

ilar

way.

Although

you

will

be using

some

frequency

settings

repeatedly,

do

not

rely

on

the

stability

of

the

instrumentover

long

periodsoftime;

the

components

are

subject

to

normal

deterioration

and

will

cause

slight

changes

of

logging

scale

settingsintime.

-8-

The

second

method

is

different

from

the

first

onlyinthe

fact

that

two

crystal

check

point

settings

are

used

in

placeoftwo

dial

markings.

First,

determine

the

number

of

logging

scale

divisions

which

correspond

to

the

frequency

difference

between

two

crystal

check

points

surrounding

the

desired

frequency;

second,

mathematically

figure

the

num

ber

of

logging

scale

divisions

the

desired

frequency

is

away

from

one

of

the

check

point

frequencies;

third,

add

or

subtract

the

determined

number

of

scale

divisions

to

or

from

the

reading

atthe

crystal

check

point.

Add

if

the

lower

check

pointisthe

reference,

or

subtract

if

the

higher

check

point

is

the

reference.

When

the

logging

scale

is

set

to

the

reading

obtainedinthe

third

step, the

oscillator

will

be

tunedtothe

desired

frequency.

The

accuracy

obtained

by

this

method

is

better

than

0.1%

A

step-by-step

exampleofthe

second

method

follows.

Again,

assume

that

a

frequency

of

20.75

mc.

is

desiredinthe

A.M.

Generator.

Note

that the

two

nearest

strong

crystal

check

points

are

20.0

and

21.67

mc.

table

1.

There

are

weak

check

points

at

21.0

and

21.25

rnc.,but

these

are

not

recommended

because

they

are

close

together

and

difficult

to

identify.

Set

the

A.M,

GENERATOR

RANGE

switch

to

B,

the

SIGNAL

switchtoGAL.,

and

the

SIGNAL

ATTENUATORS

low

to

see

the

zerobeatindications

onan

oscilloscope

with

the

VERT.

AMPL.

and

HORIZ.

AMPL.

cables

connected.

Have

the

POWER

switch

in

either

STAND

BY

or

OPERATE

position

foratleast

15

minutes

before

beginning

the

calibrationtoallow

the

Model

479

to

warm

up,

and

set

it

in

the

OPERATE

position

to

calibrate.

1.

With

the

aid

oftheoscilloscope,tunetheA.M.

GENERATOR

around

the

20

mega

cycle

point for the

zero

beat

indication.

Record

the

logging

scale

setting

for

the

zero

beat

position.

On

the

sample

unit,

the

reading

was

36.2

divisions

use

the

reading

on

your

own

Model

479;

thisisfor

an

example

only.

Retune

the

A.M.

Generator

around

the

21.67

mc.

point

for the

zero

beat

indication.

Record

the

logging

scale

setting

for

this

zero

beat

position.

On

the

sample

unit,

the

reading

was

43.3

divisions.

Subtract

the

first

reading

fromthe

second

for

the

number

of

logging

scale

divisions

between

the

check

point

frequencies.

For

the

example,

43.3-36.2

is

7.1

divisions.

2.

Determine

the

frequency

difference

between

the

desired

frequency

and

either

check

point

frequency.

In

the

example,

the

desired

frequency

20.75

mc.

is

.75

mc.

above

the

lower

check

point

and

is

.92

mc.

below

the

upper

check

point.

frequency

difference

between

the

two

check

points.

In

the

example

this

is

1.67

mega

cycles.

By

ratio

and

proportion,

the

frequency

deviations

can

be translated

into

scale

divisions

for

the

logging

scale;

F1

=

or

P1

D2

where

D1

logging

scale

divisions

between

one

check

point

and

the

desired

frequency,

D2

logging

scale

divisions

between

tyvo

check

points,

F1

frequency

difference

between

the

same

check

point

see

D1

above

and

the

desired

frequency,

and

F2

frequency

difference

between

the

two

check

points.

-9-

In

the

example,

using

the

.75

mc.

deviation

from

20

megacycles,

7.l

3.19

divisions.

3.

If

the

lower

check

point

was

used

to

determine

Di

in

step

2,

add

D1

to

the

log

ging

scale

setting

for

this

check

point;orif

the

higher

checkpoint

was

usedtodetermine

Di

in

step

2,

subtract

Dl

fromthe

logging

scale settingfor

this

check

point.

The

result

will

be

the

logging

scale

setting

for

the

desired

frequency.

In

the

example,

add

3.19

to

36.2

to

get

39.39

divisions

which

is

a

very

accurate

settingtoobtain

20.75

mc.

on

the

sample

unit.

Use

table3at

the

back

of

the

manual

to

record

the

settings

for

the

various

fre

quencies

after

they

have

been

determined.

This

will

save

timewhenever

the

use

of

any

frequency

is

repeated.

Note

that

four

columns

apply

to

each frequency

listed:

the

first

column

will

contain

the

desired

frequency;

the

second

column

will

have

the

log

scale

setting

which

has

been

determined

for

the

desired

frequency;

the

third

column

will

have

the

nearest

crystal

check

point

frequency;

and

the

fourth

column

will

have

the

log

scale

settingofthe

crystal

check

point.

To

use,

after

it

has

once

been

filled

infor

any

given

frequency,

zero

beat

the

crystal

check

point

frequency

and

compare

the

reading

of

the

logging

scale

against

the

listed

setting

of

the

fourth

column.

If

the

readings

are

identical,

tune

to

the

logging

scale

setting

of

the

desired

frequency

listedinthe

second

column

and

you

will

have

tuned

the

oscillator

to

the

desired

frequency.

However,

if

there

isadifference

between

the

log

scale

setting

for

zero

beat

at the

check

point

and

the

listed

setting

in

the

fourth

column,itindicates

that

the

components

of

the

oscillator

have

changed,

and

the

logging

scale

settings

need

correction.

If

the

log

scale

setting

for

the

crystal

check

point

has

changed

up

or

down

one,

two,or

three

divisions,

the

set

ting

for

the

desired

frequency

has

changed

the

samenumberof

divisions.

in

the

same

direction

so

add

or

subtract

the

change

to

or

from

the

column

2

listingtoprovide

a

corrected

setting.

There

is

enough

space

in

both

tbesecondandfourth

columnsto

keep

a

record

of

any

changes

overalong

periodoftime.

For

greater

accuracy,

if

the

scale

settings

change

more

than

five

divisions,

recalculate

the

column

2

listing

rather

than

add

or

subtract

divisions.

PRINCIPLES

OF

VISUAL

ALIGNMENT

The

visual

method

of

adjusting

resonant

circuits

has

been

developed

in

order

to

el

iminate

the

tedious

procedure

of

pointtopoint

measurements

which

would

otherwise

be

necessary

to

determine

the

response

characteristics

ofa

tuned

circuit

or

a

number

of

tuned

circuits

such

as

used

in

radio

and

televisions

receivers.

Referringtofigure3itisobvious

thataresponse

curve

can

be

traced

by

applying

a

signal

of

fixed

amplitude

to

the

inputofthe

circuit

and

measuring

the

output

voltage

as

the

frequency

of

the

generator

is

varied.

This,

ofcourse,requiresnumerousrreas

urements

and

is

impractical

for

the

purpose

of

circuit

adjustment.

The

visual

align

ment

procedure

accomplishes

the

same

result

but

is

instantaneous.

Here

the

gener

ator

frequencyisvaried

above

and

below

circuit

resonance

atafixed

rate.

-10-

FREQUENCY

IN

MEACYCLE

FIG.

3.

GRAPHIC

REPRESENTATION

OF

A

RESPONSE

CURVE

The

vertical

amplifier

of

an

oscilloscope

is

connected

across

the

outputofthe

cir

cuit

in

order

to

indicate

the

instantaneous

voltage

appearing

at

various

points

along

the

curve

and

the

oscilloscope

sweep

is

synchronized

with

the

generator

frequency

dev

iation

in

such

a

manner

that

the

entire

resonant

characteristicofthe

circuitisregist

ered

on

the

oscilloscope

screen.

By

this

method

the

operator

can

see

instantly

the

effectsofthe

adjustments

as

he

proceeds

with

the

alignment.

This

type

of

alignment

isofparticular

valueintelevision

receivers

because

of

the

wide

band

characteristics

necessary

for

satisfactory

reception.

ALIGNMENT

PROCEDURE

It

would

be

impossible

to

cover

all

of

the

various

alignment

procedures

in

this

man

ual

since

each

receiver

manufacturer

determines

the

sequence

of

adjustment

best

suited

to

his

particular

product.

Follow

the

receiver

manufacturer’s

service

instructions

when

making

tests

and

adjustments

on

a

television

receiver.

The

following

paragraphs

will

explain

the

various

steps

in

the

alignment

of

a

typical

receiver

andmaybeusedasa

guide

for

adaptingtheModel479

and

an

associated

oscill

oscope

to

any

manufacturer’s

specific

instruction.

The

general

procedure

is

as

follows:

1,

Connect

the

Model

479

toa110

volt

60 cycle

power

outlet.

2.

Turn

the

POWER

switchtothe

OPERATE

position.

3.

Connect

the

receiver

to

a

power

outlet

and

turn

it

on.

Adjust

the

contrast

control

to

approximately

3/4

of

maximum.

Some

receivers

requireabattery

bias

to

simulate

normal

AGG.

4.

Allow

the

receiver

and

the

Model

479

to

warm

up

for

about

15

minutes

be

fore

attempting

to

make

any

adjustments.

The

Model

479

will

not

require

additional

warm

up

timeifthe

POWER

switch has

been

left

in

the

STAND

BY

position.

-11-

5.

Connect

the

HORIZ.

AMPL.

cable

to

the

horizontal

input

terminals

of

the

oscilloscope,

and

the

VERT.

AMPLJ.

cable

to

the

vertical

amplifier

input.

6.

Set

the

oscilloscope

switches

and

controls

as

follows:

vertical

sensitivity

high,

vertical

gain

at

0,

horizontal

gain

as

required

to

obtainaconvenient

horizontal

deflection

on

the

cathode

ray

tube,

and

function

switch

to

the

position

which

will

connect

the

horizontal

input

through

the

horizontal

amplifier.

7.

Advance

the

oscilloscope

intensity

control

and

focus

control

until

a

thin

bright

horizontal

lineisseen

on

the

cathode

ray

tube.

Center

the

trace

horizontally

and

vertically.

8.

On

the

Model

479,

set

the

controls

as

follows:

F.M.

GENERATOR

RANGE

switchatOFF:

A.M.

GENERATOR

RANGE

switch

to

B;

SIGNAL

switchtoGAL.,

and

SIGNAL

ATTENUATORS

low.

9.

Advance

the

oscilloscope

vertical

gain

control

to

about

mid

rotation

and

re

adjust

as

desired

during

the

following

steps.

10.

Refer

to

the

receiver

manufacturer’s

literature

for the

frequencies

which

will

be

required

during

the

adjustment.

Determine

the

logging

scale

settingstotune

these

frequencies;

use

the

instructions

givenunder

CALIBRATION

PROCEDURE

in

this

man

ual.

The

frequencies

specified

for

this

example

of

a

typical

circuit

are;

19.75,

21.25,

21.8,

22,3,

23.4,

25.2,

25.3,

and

27.25

mc,

Seefigure4.

Anewtendencyamong

receiver

manufacturers

is

to

use

an

intermediate

frequency

centered

around

45

mc.

ll.

Set

the

OUTPUT

cable

termination

for

75

ohms

by

jumpering

terminals

6-

7-8-9-5

and

terminals

2-3-4.

Open

termination

may

be

preferred.

See

table

2

for

instructions.

Connect

the

alligator

cliponthe

end

of

the

probe

to

point

"F

"

of

figure

4.

Connect

the

ground

lead

of

the

probe

to

the

receiver

chassis.

Note

that

the

alligator

clip

and

ground

lead

may

provide

too

much

inductance

for

use

at

45

mc

See

the

special

instructions

on

page

24.

Connect

the

SIGNAL

INPUT

cable

to

point

A

"of

figure

4.

fcowvrg

AUDIOI

‘

-

DT

12.

Rotate

the

SIGNAL

switch

to

MOD.

R.F.

and

adjust

the

SIGNAL

ATTEN

UATORS

and

the

oscilloscope

vertical

gain

control

untilagood

size

Lissajou

pattern

is

seen

on

the

oscilloscope.

The

SIGNAL

ATTENUATORS

shouldbeoperated

at

the

lowest

setting

which

will

give a

good

oscilloscope

pattern.

13.

SettheA.

M.

GENERATOR

logging

scale

to

the

point

recorded

for

19.75

meg

acycles

and

adjust

L7

point

"1

"of

figure

4

for

minimum

patternheight.

If

the

pattern

disappears

completely,

increase

the

attenuator

setting

until

the

exact

minimum

point

can

be

observed.

14.

Set

the

logging

scaleatthe

point

recorded

for

21.25

mc.

and

adjust

the

sound

FIGURE.

4.

TYPICAL

TV

VIDEO

IF

SYSTEM

-12-

takeoff

trap

L3

point

2

for

a

minimum

indication.

15.

Leave

the

Model

479

set

at

21.25

mc.

and

adjust

the

accompanying

sound

trap

L9

point

3

for a

minimum

indication.

16.

Set

the

logging

scaletothe

point

recordedfor

27.25

mc.

and

adjust

the

ad

jacent

channel

sound

trap

L5

point

4

for

a

minimum

indication.

This

completes

the

trap

adjustments.

17.

Set

the

logging

scaleatthe

point

recorded

for

21.8

mc.

and

adjust

the

con

verter

output

LZ

point5for

a

MAXIMUM

indication.Ifthe

pattern

becomes

too

large,

reduce

the

SIGNAL

ATTENUATORS.

18.

Set

the

logging

scale

to

the

point

recorded

for

25.3

mc.

and

adjust

the

first

IF

L4

point

6

for

maximum.

19.

Set

the

logging

scale

to

the

point

recorded

for

22.3

mc.

and

aojust

the

second

IF

L6

point7for

maximum.

20.

Set

the

logging

scaletothe

point

recorded

for

25.2

mc.

and

adjust

the

third

IF

L8

point8for

maximum.

21.

Set

the

logging

scale

to

the

point

recorded

for

23.4

mc.

and

adjust

the

third

IF

Lii

point

9

for

maximum.

22.

If

coils

L2,

L4,

and

L6

have

required

appreciable

adjustment,

the

associated

traps,

L3,

L5,

and

L7

should

be

rechecked

as

explained

in

steps

13,

14,

and

16.

23.

Occasionally

a

receiver

will

haveatendencytooscillate

during

alignment.

Usually

this

is

caused

bytwo

or

more

transformers

being tuned

to

the

same

frequency.

Such

oscillationwill

be

identified

by.a

suddenhigh

deflectiononthe

CRT

and

a

scrambled

patternwhich

cannot

be

controlled

bythe

attenuators.

When

this

occurs,

the

best

remedy

is

to

shunt

points

C,

D,

E,

andFwith

.001

mfd

capacitors.

Connect

the

Model

479

OUTPUT

cable

to

pointBand

adjust

Lii.

Remove

the

capacitor

at

pointCand

connect

the

OUTPUT

CABLE

to

this

point

and

adjust

L8.

Repeat

this

process

for

each

stage

back

to

pointF,removing

the

capacitor

and

connecting

the

OUTPUT

cabletopoints

D,

E,

and

F.

Adjust

L6,

L4,

and

L2

for

maximum

indications.

Some

manufacturers

rec

ommend

the

latter,orbackwards,

sequence

of

adjustment.

It

makes

little

difference

which

sequence

is

used

as

long

as

each

stageisadjusted

carefully

to its

assigned

fre

quency.

This

completes

the

i-f

adjustments.

24.

Leave

the

OUTPUT

cable

of

the

Model

479

connectedtothe

converter

grid

point

F

and

the

SIGNAL

INPUT

cable

connected

across

the

video

detector

load

resis

tor

point

A.

25.

Set

the

SIGNAL

switch

to

the

OFF

position.

Set

the

F.M.

GENERATOR

RANGE

switch

to

A,

F.

M.

ATTENUATOR

switch

to

MAX.

and

potentiometer

to

5,

PHASING

to

0,

and

BLANKING

to

OFF.

Tune

the

F.M.

GENERATOR

to

approximately

23

mc.

on

range

A.

A

response

curveofthe

i-f

systemwill

appear on

the

oscilloscope.

Adjust

the

F.M.

Attenuators

and

the

oscilloscope

vertical

gain

forapattern

of

cpnven

ient

height,

keeping

the

F.

M.

ATTENUATORS

set

as

low

as

possible.

Adjust

the

PHASING

controltosuperimpose

the

two

traces.

Readjustthe

tuning

dial

until

the

pat

tern

is

centered

in

the

horizontal

trace.

Readjust

the

F.M.

SWEEP

control

until

the

patternincludesabouttwo-thirds

of the

horizontal

trace.

Correct

the

control

for

super

imposed

traces

again.

Rotate

the

BLANKING

control

to

produce

a

base

line

through

a

single

trace.

-13-

25,7

a5.75

FIG.

5.

PICTURE

IF

RESPONSE

-

STAGGER

TUNED

26.

Compare

the

pattern

with

the

one

shown

in

the

manufacturer’s

instruc

tions.

Figure

5

shows

an

example

of

an

i-f

response

curve.

If

the

system

has

been

aligned

properly,

it

should

resemble

figure

5A.

27.

Turn

the

SIGNAL

switch

to

UNMOD.

R.F.

and

set

the

logging

scaleofthe

A.M.

Generator

to

the,

point

for

22.3

mc.

A

marker

should

appear

on

the

pattern

as

shown

at

the

left

in

figure

5

A,

B,

and

C.

Adjust

the

SIGNAL

ATTENUATORS

and

the

F.M.

ATTENUATORS

for the

desired

balance

of

signal

strengths.

If

the

marker

sig

nalistoo

strong,

the

curve

will

be

distorted

and

it

willbedifficult

to

measure

its

exact

position

on

the

pattern.

28.

Set

the

logging

scaletothe

point

recorded

for

25.75

mc.

and

check

the

pos

itionofthe

marker.

It

should

appear

at

50%

of

the

maximum

pattern

height.

Setting

the

marker

frequency

to

the

various

pointstowhich

the

system

was

adjusted

will

in

dicate

the

part

of’

the

response

curve

affectedbyeach

adjustment.

Slight

re-adjust

ment

of

the

systemmay

be

performed

at

these

points

inorderto

produceasatisfactory

response

curve.

However,

if

considerable

adjustment

is

necessary,

the

entire

align

ment

procedure

should

be

repeated.

The

foregoing

paragraphs

have

dealt

with

the

alignment

of

a

stagger

tuned

video

i-f

system.

Another

system,

known

as

Band

Pass

IF

and

used

in

many

receivers,

requires

that

the

entire

alignment

be

performed

by

use

of

the

F.M.

Generator.

In

this

type

of

receiver,

alignment

begins

with

the

last

i-f

stage

and

proceeds

stage

by

stage

back

to

the

converter.Aset

of

curves

is

furnishedasa

guide

anditis

only

necessary

to

follow

the

sequence

set

up by

the

manufacturer’s

instructions,

using

his

curves

to

indicate

the

type

ofresponse

to

be

expected.

A

set

of

sample

curves

appears

in

figure

6.

To

adjust

band

pass

i-f,

connectthe

SIGNAL

INPUT

cable

to

the

video

detector

out

put

and

the

OUTPUT

cabletothe

grid

of

the

last

i-f

amplifier.

Set

the

F.M.

GENER

ATOR

RANGE

switchtoA

and

adjust

the

dial

to

25

mc.

Set

the

F.M.

ATTENUATORS

to

MAX.

and

10,

and

adjust

PHASING

and

BLANKING

controls

and

the

associated

os

cilloscope

for a

single

image

pattern

with

satisfactory

,height.

Set

the

A.M.

GENER

ATOR

RANGE

switch

toBand

the

SIGNAL

switch

to

CAL.

Record

logging

scale

read

ings

for

the

recommended

frequencies.

In

the

example,

these

are

22.6,

22.75,

23.25,

23.75,

24.25,

‘24.6,

25.75,

26.6,

26.75,

27.0,

and

27.1

megcycles.

Set

the

SIGNAL

switchtoUNMOD,

R.F.

andthe

logging

scale

tothepoint

recorded

for

27.1

rnegacycles.

Adjust

the

SIGNAL

ATTENUATORS

to

the

lowest

setting

which

will

give

a

satisfactory

marker

on

the

trace.

Adjust

the

last

i-f

transformer

primary

and

secondary

for

a

single

peak

centered

on

the

27.1

mc.

marker.

Setthe

A.M.

Generatorloggingscaletothepos

ition

for

23.25

mc.

Adjustthe

coupling

condenserinthe

last

i-f

transformer

for

a

peak

centeredat2325

mc.

The

curve

should

now

resemble

figure

6A.

A

ftPRO?ERLY

PLtGt4ED

MPROPERL’

ALIGNED

-14-

80

60 40

20

0

FIG.

6

VIDEO

ALIGNMENT

CURVES

-

BAND

PASS

TYPE

Move

the

OUTPUT

cable

to

the

grid

of

the

preceding

stage.

Adjust

the

secondary

of this

i-f

transformer

fora

peak

at

23.75

mc.

and

the

primary

forapeak

at

26.75

mc.

There

is

no

coupling

condenser

adjustment

for

this

stage.

The

response

curve

should

now

resemble

figure

6B.

Move

the

OUTPUT

cable

to

the

stage.

Adjust

the

primary

and

sec

ondary

of

the

i-f

transformer

for

a

curve

having

the

same

shape

and

relative

amplitude

as

that

of

figure

6G.

Use

the

marker

at

the

frequencies

indicated:

22.75,

24.25,

25.75,

and

27.0

mc.

Move

the

OUTPUT

cabletothe

gridofthe

converter.

Adjust

the

primary,

secondary,

and

coupling

condenser

of

the

first

i-f

transformer

foracurve

having

the

same

shape

and

relative

amplitude

as

figure

6D.

The

check

points

indicated

for

marker

use

are

22.6,

23.75,

24.6,

and

26.6

megacycles.

Touch

up

adjustments

are

permissable

to

improve

the

over-all

response

curve.

Be

careful

to

select

the

adjustment

which

affects

the

partof

the

curve

which

needs

correc

tion.

Figure

7

shows

the

acceptable

limits

of

the

over-all

response

curve

with

the

amplitudeat24.0

mc.

for

a

reference

point.

Conduct

the

alignment

to

produce

a

curve

which

is

within

these

tolerances.

The

last

five

paragraphs

have

outlined

a

typical

process

for

band

pass

i-f

align

ment

only.

For

trap

adjustments,

see

steps

10

to

16

on

page

12.

The

trapadjustments

should

be

made

in

the

order

recommended

by

the

receiver

manufacturer,

with

the

F.M.

GENERATOR

RANGE

switch

in

the

OFF

position

and

the

SIGNAL

switchinthe

MOD.

R.F.

position.

Log

the

specified

trap

frequencies

in

advance.

oc

-+

,

U

,O

+

*

-

40

20

0

f

ITTE

2

23

24

25

26

27

A

Tr:J

LU

J

z

0 U

LU

t:t

LU >

F

t

26

EL

I

i

I

234

25

26 27

28

22

23

24

25

26

27

28

2’342526I

FREQUENCY

MC

D

-15-

*1r

1f

ik

UF

1Uft

0

2

24

25

25$

27

PICIURE

i-F

T0LRANCE

FIGURE

7.

RESPONSE

TOLERANCE

-

BAND

PASS

I-F

A

third

type

of

circuit

uses

what

is

known

as

intercarrier

i-f.

The

principle

is

to

provide

a

mixer

and

oscillator

to

produce

an

intermediate

frequency,

and

to

ampli

fy

this

i-f

through

several

stages

with

a

special

frequency

response

characteristic;

the

band

pass

is

sufficienttoinclude

both

the

sound

and

the

video

center

frequencies,

and

the

response

maintainsadesired

relative

amplitude

between

the

two

center

frequencies.

Then

the

beatof4.5

megacycles

between

the

two

center

frequencies

is

used

to

produce

a

double

superheterodyne

action

with

the

sound

frequency

modulated

on

the

4.5

mc.

carrier.

The

sound

i-f

isuaiiy

one

stage,

tunedto4.5

mc.,

aLnpiifies

the

sound

sig

nal

and

sendsitto

an

f-rn

demodulator

of

any

type

desired

by

the

manufacturer.

It

is

important

to

follow

the

alignment

data

indicatedinthe

manufacturer’s

literature

be

cause

he

has

engineeredacircuit

which

requires

specific

response

characteristics1

and

no

generalization

could

represent

the

large varietyofpossibilities.

The

receiver

manufacturer’s

literature

will

indicate

where

the

test

points

are

located,

what

fre

quency

to

use

for

each

input,

what

adjustment

can

be

made,

and

the

resulting

response

wave

shape.

Set

up

the

Model

479

in

accordance

with

general

instructions

and

use

an

oscilloscopetoobserve

the

results.

Use

the

6O

sweep

available

through

the

HORIZ.

AMPL.

cabletoobserve

the

response

curve

in

phase

with

the

frequency

modulating

signal.

Sometimes

during

alignment

it

is

desirabletohave

two

markers

at

different

fre

quencies

on

the

response

curve

at

the

same

time.

A

second

signal

generator,

unmod-

ulated,isnecessary,

tunable

to

the

frequency

at

which

the

marker

is

desired.

The

second

generator

can

be

calibrated

with

the

accuracyof

the

Model

479

and

should

be

as

stable

as

possible.

To

calibrate

the

second

generator,

set

up

the

Model

479

for

its

normal

alignmentprocedure,

withthe

OUTPUTfeedinginto

a

receiver

and

the

receiver

output

connected

to

the

SIGNAL

INPUT

cable.

Connect

the

VERT.

AMPL.

and

HORIZ.

AMPL.

cables

to

the

input

terminals

of

the

associated

oscilloscope.

Establish

the

marker

on

the

response

curve

at

the

frequency

to

which

the

second

generator

will

be

tuned.

Then

couple

the

second

signal

generator

outputacross

the

termination

box

or

in

any

other

convenient

way

to

the

receiver

input.

Sometimes

the

mere

presence

of

the

second

generator

on

the

test

bench

will

provide

sufficient

coupling

without

any

direct

connections.

Now

tune

the

second

signal

generator

for

a

beat

indication

with

the

marker

from

the

accurately

calibrated

A.M.

Generator

in

the

Model

479.

Tune

the

second

gen

erator

forazero

beat

indicationofthe

two

markers.

Then

change

the

settingofthe

Model

479

A.M.

Generator

to

provide

the

second

marker

frequency.

Both

markers

will

show

on

the

single

response

curve.

F-M

RECEIVER

ALIGNMENT

The

order

of

f-rn

alignment

usually

begins

with

the

discriminator

adjustment;

the

i-f

section

is

the

r-f

section

is

last.

If

the

receiver

manufacturer

recommends

some

other

sequence,

use

his

suggestions

rather

than

these

general

instructions.

The

-16-

informationin

the

followingparagraphsisforthe

sound

section

of

a

television

receiver,

but

the

same

principles

apply

to

f-rn

receivers

except

that

their

intermediate

frequencies

are

usually_lower,

Figure

8

is

the

schematic

diagramofa

typical

sound

i-f

system

composed

of

three

i-f

amplifier

stages

andadiscriminator.

Thethird

i-f

stage

acts

asalimiter

to

reduce

the

effectsofamplitude

modulation.

Usually

the

alignment

will

begin

at

the

discrim

inator

and

work

back,

stage-by-tage,

to

the

converter.

Proceed

as

follows:

1.

Connect

the

HORIZ.

AMPL.

cable

and

the

VERT.

AMPL.

cable

to

the

input

terminalsofthe

associated

oscilloscope.

2.

Connect

the

Model

479

OUTPUT

cable

between

point

"C

H

and

ground

see

figure

8.

Use

any

desired

termination.

See

table

2

for

data

on

the

termination

box

connections.

Use

the

series

condenser

do

not

jumper

terminals

1

and

6.

3.

Connect

the

SIGNAL

INPUT

cable

between

point

"A

"

and

ground

figure

8.

4.

Set

the

F.M.

ATTENUATORS

to-

MAX.

and

10,

F.M.

SWEEP

to

1,

PHASING

to

0,

BLANKING

to

OFF,

F.M.

GENERATOR

RANGE

to

B,

and

CENTER

FREQUENCY

dial

pointer

to

21.25

mc.

the

intermediate

frequency.

5.

Set

the

oscilloscope

controlstoproduce

a

convenient

horizontal

trace

cent

ered

on

the

face

of

the

cathode

ray

tube.

Set

the

oscilloscope

function

control

so

the

60

cycle

sine

wave

voltage,

fed

through

the

HORIZ.

AMPL.

cable,isthe

horizontal

deflect

ing

signal.

6.

Advance

the

oscilloscope

vertical

gain

until

the

pattern

is

one

to

two

inches

high.

The

pattern

will

be

two

S-shaped

response

curves.

Adjust

the

PHASING

control

to

bring

the

curves

in

phase

as

shown

in

figure

9.

FIG.

9.

DISCRIMINATOR

RESPONSE

-

IN

PHASE

-

BLANKING

OFF

7.

Adjust

the

F.M.

SWEEP

so

the

response

curve

covers

most

of

the

trace

as

shown

in

figure

9.

Readjust

the

PHASING

controlifthe

traces

separate.

If

the

response

FIG.

8.

TYPICAL

TV

SOUND

IF

SYSTEM

DISCRIMINATOR

ALIGNMENT

-17-

curve

is

not

centered

on

the

trac-e,

reset

the

CENTER

FREQUENCY

pointer

to

center

the

pattern.

Advance

the

BLANKING

controltoproduce

a

pattern

as

shown

in

figure

10;

thisisa

single

curve

with

a

base

line

through

it.

4

FIG.

10.

DISCRIMINATOR

RESPONSE

-

BLANKING

ADJUSTED

8.

Reduce

the

F.M.

ATTENUATORS

and

advance

the

oscilloscope

vertical

gain

for

the

lowest

attenuator

setting

which

givesasatisfactory

pattern.

9.

Set

the

SIGNAL

switch

to

CAL.,

A.M.

GENERATOR RANGE

to

B,

SIGNAL

ATTENUATORS

low,

and

adjustthe

frequency

to

exactly

21.25

mc.

see

CALIBRATION

PROCEDURES

on

page

5

.

10.

Turn

the

SIGNAL

SWITCH

to

MOD.

R.E.

A

pattern

similar

to

figure

ii

will

appear on

the

oscilloscope

if

the

discriminator

secondary

is

not

aligned

perfectly.

Re-

duce

the

SIGNAL

ATTENUATORS

to

as

lowasetting

as

possible

with

the

400

cycle

pattern

still

showing.

FIG.

II.

DISCRIMINATOR

RESPONSE

-

400

CYCLE

MODULATION

11.

Adjust

the

discriminator

secondary

L9

in

figure

8

until

the

400

cycle

pattern

disappears

and

then

re-appears

if

the

adj1stment

is

continued

in

the

same

dir

ection.

Be

sure

to

make

this

adjustment

to

the

exact

null

point

with

the

SIGNAL

ATTENUATORS

set

low

to

avoidabroad

response

due

to

a

high

signal

amplitude.

12.

Adjust

the

discriminator

primary

L8

in

figure8until

a

maximum

ampli

tude

symmetrical

patternisachieved

as

shown

in

figure

7.

Reduce

the

F.M.

ATTEN

UATOR

settingasthe

amplitude

of

the

curve

increases.

Readjust

the

secondary

if

the

400

cycle

modulation

reappears.

13.

Move

the

OUTPUT

cable

to

the

gridofthe

stage

point

"D"

in

figure

8.

14.

Move

the

SIGNAL

INPUT

connectiontothe

gridofthe

limiter

point

‘C

‘

in

figure

8.

15.

Turn

the

SIGNAL

switchtoUNMOD.

R,F. and

adjust

the

F.M.

and

SIGNAL

ATTENTJATORSto

obtainani-f

response

curve

similar

to

figure

12.

The

curve

may

be

distorted

until

the

has

been

made.

-18-

-

–1

t

tt-r-ht-+-tt

_:t

-

FIG.

12.

SOUND

I-F

RESPONSE

16.

Adjust

L7

and

L6

of

figure

8

forasymmetrical

response

of

maximum

height

similartofigure

12.

The

marker

should

appear

at

the

center.

Keep

the

F.M.

ATTEN

UATORS

set

as

low

as

possible

to

avoid

overloading

and

keep

the

SIGNAL

ATTEN

UATORS

set

low

to

avoid

distortion

of

the

response

curve

at

the

marker

point.

17.

Connect

the

OUTPUT

cable

to

the

gridofthe

stage

point

in

figure

8.

Adjust

L5

and

L4

for

a

symmetrical

response

curve

of

maximum

height

as

in

step

16

above.

The

sound

i-f

adjustment

is

now

complete.

Adjustment

of

L2

and

L3

was

cov

ered

in

video

i-f

alignment.

However,

if

this

were

an

f-rn

receiver

insteadofa

tele

vision

receiver,

L2

and

L3

would

be

adjusted

to

the

intermediate

frequency

with

the

OUTPUT

cable

coupled

to

the

converter

grid.

As

the

alignment

proceeds

from

the

dis

criminator

back

to

the

converter,thewidthof

the

response

curvewilidecrease

sincethe

selectivityofthe

entire

amplifier

is

greater

than

that

of

any

one

stage.

If

the

response

curve

becomes

too

small,

reduce

the

F.M.

SWEEP.

Any

change

in

sweep

width

will

re

quire

re-adjustment

of

the

PHASING

control.

Adjust

the

PHASING

control

with

BLANK

ING

at

OFF.

Ifitis

desired

to

check

the

band

pass

of

the

i-f

system,

connect

the

OUTPUT

cable

to

the

grid

of the

converter

tube

and

move

the

marker

with

the

A.M.

Generator

from

one

sideofthe

response

curve

to

the

other.

i

-

t?tLf

IJiL1

T

tbf

LLti

hUId

-RJEC’

FIG.

13.

I-F

BAND

PASS

MEASUREMENT

The

band

passofa

resonant

circuit

is

usually

taken

between

the

70%

response

points.

See

figure

13.

To

check

the

band

pass

of

the

i-f

system,

set

the

A.M.Generator

tuning

knob

to

place

the

marker

on

the

response

curve

at

the

70%

point

on one

side

of

the

curve.

Record

the

frequency

indicated

on

the

A.

M.

Generator

dial.

Then

move

the

marker

to

the

70%

response

pointonthe

other

side

of

the

curve.

Record

the

frequency

indicatedontheA.M.

Generator

dial

again.

Then

subtract

the

lower

recorded

frequency

from

the

higher

for

the

band

of

frequencies

passed

‘.

-19-

TELEVISION

TUNER

ALIGNMENT

Many

of

the

present

day

television

sets

use

an

r-f

tuning

unit

produced

by

Standard

Coil

Products

Co.

This

unit

containsa12-position

rotary

channel

selector

together

with

a

stageofr-f

amplification,

an

r-f

oscillator,

and

an

r-f

mixer.

The

components

are

matched

for

the

purpose

of

transferring

the

modulation

on

the

tuned

signal

to

an

intermediate

frequency.

The

various

receiver

manufacturers

who

use

this

tuner

have

used

slightly

different

center

intermediate

frequencies,

and

some

have

used

separate

i-f

strips

for

sound

and

video,

while

others

have

used

intercarrier

i-f

amplification.

The

tuner

can

be

adjustedtoproduce

whateveroutputthe

manufacturer

requiresfor

his

circuit,

and

manufacturer’s

literature

will

indicate

the

center

frequency

and

the

wave

form

required

for

servicing

his

equipment.

Admiral

Corporation,

for

an

example,

uses

the

Standard

Coil

Products

tuner

dia

grammed

in

figure

14aintheir

2lBl,21C1,

and

5D2

chassis.

It

is

adjusted

to

tune,

in

the

r-f

amplifier,adouble

peaked

curve

with

the

center

frequencies

of

the

sound

carrier

and

the

video

carrieratthe

peaks and

not

more

than

30%

reductioninresponse

to

frequencies

within

this

4.5

mc.

range.

Then

the

intermediate

frequency

output

is

balanced

so

that

after

ithas

passed

through

the

i-f

amplifiers,

the

center

video

carrier

FIG.

14.STANDARDC

68/c’7/68Q7

P4MP

A,c

RTQ

c

W/1I76

&ACk

&eJE

‘3V

24C-260V

A

CIRCUIT

FOR

TV-114,

214,

293

-20-

is

on

one

slope

of

the

curve

ata

50%

response

point,

and

the

center

sound

carrier

is

on

the

other

sideofthe

curve

ata5%

response

point.

The

same

pair

of

wave

shapes

need

to

be

produced

for

each

of

the

12

channels.

Each

channel

hasapair

of

tuned

cir

cuits

with

switch

points

which

make

all

the

necessary

connections

to

tune

both

the

re

ceived

signal

and

the

local

oscillator

for

the

frequencies

necessaryfor

the

channel.

The

tuning

problem

consistsofadjusting

slugs

for

eachofthe

12

bands

which

insure

that

the

maximum

signal

strength,

with

proper

amplitude

proportions

for

its

component

fre

quencies,

will

come

outofthe

mixer.

In

general,

the

manufacturer

will

specifyaninput

across

the

antenna

terminals

at

the

center

frequency

of

the

channel,

frequency

modulated

througharange

of

10

mega-

cycles

or

more,

and

marked

at

the

video

carrier

frequency

and

the

sound

carrier

fre

quency.

Use

the

OUTPUT

cable

for

this

connection

and

set the

termination

box

for

the

characteristic

impedance

of

the

antenna

terminals

see

table

2.

Connect

the

SIGNAL

INPUT

cable

at the

r-f

test

point

ontopof

the

tuner

chassis

between

the

two

tubes.

The

circuit

position

for

this

testpoint

shows

infigure

l4Aand

B.

Adjustther-f

stage

tuning.

Then

move

the

SIGNAL

INPUT

cabletothe

check

point

probably

in

the

i-f

amplifier

and

adjust

the

oscillator

tuning

for

the

specified

response

curve.

TURQE

$M’TCN

SETTING

SELECTS

COILS

FOR’

ChANNEL

DE$/QED

RF.

TEST

Poiwr

RODUCTS

TUNtRS

B.

CIRCUIT

FOR

TV-2000

SERIES

-21-

VIDEO

CARRIER

SOUND

CAIRIER

MARKER

MAR

DIP

5HOULDOT

HEIGHT

EXCEED

3db

OR

30%

OF

TOTAL

FULL

5KIRT

OF

CURVE

WILL

NOT

BE

VIBLE

UHLES5

GENERATOR

SWEEP

WIDTH

EXTEND5

BEYOND

10

MC.

A

R.F.

RESPONSE

DIFFERENCEINHEIGHTOFPEAKS

a

3db

MUMUM3O%

/H0ULD

NOT

EXCEED

3db

OR

30%

:EORRtER

ATA5T

26db

POINT

AGdbO

MARKER

A

MEASURED

FROM

HIGHE3T

PEAK

B.

OVERALL

R.F.

AND

I.F

RESPONSE

FIG.

15.

TYPICAL

TV

TUNER

RESPONSE

F.

M.

TUNER

ALIGNMENT

Frequency

modulation

receivers

have

the

following

sections:

r-f

tuner,oscillator,

mixer,i-f

amplifier,

limiter,

discriminator,

and

a-f

amplifier.

The

procedure

for

align

ing

the

i-f

amplifier,

limiter,

and

discriminator

is

identical

to

the

procedure

for

the

sound

section

of a

television

receiver

except

that

the

intermediate

frequency

for

f-rn

receivers

is

usually

10.7

mc.

See

page

17

for

this

data.

The

general

type

of

instructions

for

adjustment

of

the

r-f

tuner,

oscillator,

and

mixer

can

be

outlined,

but

the

exact

and

complete

procedure

will

vary

from

one

man

ufacturertoanother.

Most

receivers

have

provision

for

adjustment

hear

the

high

end

of

the

dial

108

mc..

Some

havealow

frequency

adjustment

in

addition.Itis

advis

able

to

consult

manufacturer’s

literature

to

obtain

the

recommended

frequency

or

fre-

quencie

s.

1.

Connect

the

VERT.

AMPL.

and

HORIZ.

AMPL.

cables

to

the

vertical

and

horizontal

input

terminals

of

the

associated

oscilloscope.

Set

the

oscilloscope

function

control

so

the

input

at

the

horizontal

input

terminals

is

sent

through

the

horizontal

amplifier.

-22.-

2.

Connect

the

SIGNAL

INPUT

cable

across

the

outputofthe

demodulator

stage

point

uA

in

figure

8.

3.

Connect

the

OUTPUT

cable

through

its

matching

network

to

the

antenna

terminals

of

the

receiver.

Connect

the

termination

box

according

to

the

dataintable

2

to

provide

the

correct

input

for

the

receiver.

Manufacturerts

instructions

should

indicate

whether

this

is

75

ohms

or

300

ohms.

4.

Set

the

A.M.

Generator

to

the

frequency

recommended

for

alignment.

Use

the

CALIBRATION

PROCEDURE

page

5

to

set

this

exactly.

Set

the

receiver

dial

at

the

same

frequency.

5.

Rotate

the

SIGNAL

ATTENUATORS,

F.M.

ATTENUATORS,

and

the

oscill

oscope

vertical

gain

for

a

400

cycle

pattern

with

satisfactory

height.

6.

Adjust

the

oscillator,

mixer,

and

r-f

trimmers

of

the

receiver

to

obtain

a

maximum

amplitude

pattern.

Keep

the

SIGNAL

and

F.M.

ATTENUATORS

as

low

as

possible,

but

keep

a

usable

pattern

on

the

cathode

ray

tube.

An

alternate

to

the

above

method

uses

a

frequency

modulated

signal input

to

the

antenna,

with

a

marker

signal

set

at

the

desired

frequency.

Adjust

the

oscillator,

mixer,

and

r-f

trimmers

of

the

receiver

for

a

symmetrical

response

curve

with

a

maximum

amplitude,

and

with

the

marker

centered

on

the

curve.

Note

that

these

instructions

are

very

general.

They

are

intended

as

a

theoret

ical

idea

of

alignment

only.

Always

consult

the

receiver

manufacturer’s

instructions

for

specific

directions

when

aligning

his

sets

and

follow

them.

However,

an

oscill

oscope

can

be

used

to

advantage

in

addition

to

the

vacuum

tube

voltmeter

specified

in

many

instructions.

The

oscilloscope

will

show

the

shape

of

the

response

wave

form.

FIG.

16.

IMPEDANCE

MATCHING

OUTPUT

CABLE

-23-

TABLE

2.

TERMINATION

BOX

CONNECTIONS

TERMINATION

CONNECTIONS

300

OHMS

JUMPER

7-8-9-5

JUMPER

3-4

300

OHM

WITH

PAD*

JUMPER

3-8

JUMPER

5-9

75

OHMS

JUMPER

6-7-8-9-5

JUMPER

Z-3-4

75

OHM

WITH

PAD*

JUMPER

6-7

JUMPER

Z-3-8

JUMPER

5-9

OPEN

TERMiNATION

JUMPER

2-3-4

JUMPER

6-7-8-9

SERIES

CAPACITOR

NO

JUMPER

1-6

USE

IN

ADDITION

TO

JUMPER

1-6

TERMINATIONS

INDICATED

ABOVE,

RESISTANCE

COUPLING,

NO

SERIES

CAPACITOR

*THE

USE OF

A

PAD

PROVIDES

1000

OHMS

IN

SERIES

WITH

EACH

SIDEOF

THE

LINE

USING

OUTPUT

CABLE

TERMINATION

BOX

In

order

to

simulate

actualoperating

conditions,

it

is

important

that

the

receiver

input

impedance

and

the

generator

output

impedance

are

matched.

The

OUTPUT

cable

for

the

Model

479

has

a

termination

box

built

on

the

probe

end

to

facilitate

matching

these

impedances.

See

figure16and

table2foranoutline

drawing

of

the

probe

and

some

of

the

possible

connections.

The

two

most

commonlyusedirnpedances

for

receiver

in

puts

are

75

ohms

and

300

ohms.

These

are

both

available,

with

or

without

an

isolating

pad,

by

simply

connecting

bare wire

jumpers

as

indicated

in

table

2.

In

each

case,

the

connections

are

set

to

providea75

ohm

termination

for

the

Model

479

output

because

this

value

is

proper

for

its

output

characteristics.

Use

of

the

pad

provides

isolation

between

the

output

of

the

Model

479

and

the

receiver

points

to

which

itisconnected.

If

a

series

capacitor

of

2000

uuf

is

desired

in

series

with

the

receiver

input

for

d-c

blocking,donot

jumper

terminals1and

6,

but

if

a

straight

resistance

coupling

is

de

sired,

jumper

these

terminals

to

short

the

capacitor

whichis

built

into

the

termination

box.

An

open

termination

is

provided

for

optional

use:

whenusing

this

connection,

the

Model

479

output

is

not

impedance

matched,

but

each

side

of

the

outputisconnected

straight

through

with

the

series

capacitorifdesired

to

the

two

sidesofthe

receiver

input.

When

operating

in

the

new

intermediate

frequency

range

around

45

mc.,

the

term

ination

box

may

cause

distortionofthe

response

wave

form.

For

best

results,

change

the

termination

box

connections

as

follows:

1.

Pull

the

alligator

clip

off

the

post

on

the

endofthe

termination

box

near

screw

terminal

number

1.

2.

Cut two

pieces

of

solid

bare

jumper

wire,

#20

or

22,

1-3/4

inches

long

and

one

piece

1

inch

long.

3.

Loosen

screws

2,

3,

and

4,and

place

one

1-3/4"

wire

under

them

so

that

it

is

straight

between

the

screws

and

then

bends

around

s’crew

number

2

with

about

1/2

inch

extending

beyond

the

side

of

the

termination

box.

Tighten

the

screws.

This

will

be

the

ground

lead.

4.

Loosen

screws

6,

7, 8,

and

9.

Place

the

other

1-3/4"

wire

under

these

screws.

Keep

the

wire

straight

and

tighten

the

screws.

5.

Loosen

screw

number

1

and

place

one end

of

the

1"

wire

under

it.

With

the

wire

extending

off

the

side

of

the

termination

box,

tighten

the

screw.

This

will

be

the

"hot"lead.

-24-

6.

Solder

the

"hot

lead

to

the

connection

point

of

the

receiver

and

the

ground

lead

to

the

chassis

or

receiver-ground.

This

provides

an

open

terrninationfor

the

cable,

with

the

2000

uuf

capacitor

in

series.

It

is

important

to

keep

the

leadsofthe

probe

very

shorttoobtain

efficient

operation.

An

alternate

method

of

handlingthis

problemisto

make

up

a

special

output

cable

to

use

for

45

mc.

An

Amphenol

type

80M

cable

connector,about

3

feet

of

RG-59/U

cable,

anda1000

uuf or

2000

uuf

ceramic

capacitor

are

all

the

required

parts.

Attach

the

connector

on

one

end

of

the

cable

and

solder

one

lead

of

the

capacitor

clip

the

lead

short

to

the

center

conductor

at

the

other

end

of

the

cable.

Solder

the

other

capacitor

lead

to

the

connection

pointinthe

receiver

and

the

cable

shieldtothe

chassis

or

re

ceiver

ground.

A

special

OUTPUT

cable

assembly,

Simpson

part

number

10-830046,

for

use

at

45

n-ic.,isnow

available

as

an

accessory

to

owners

of

the

Model

479.

Should

other

termination

boxconnections

than

those

listed

in

table

2

be

desired,

they

may

be

obtained

by

using

resistors

between

the

terminals

rather

than

using

jumper

wires.

Suppose

150

ohms

were

desired.

Connect

a

jumper

across

terminals5and

9

to

provide

the

proper

termination

for the

Model

479.

Then

connecta75

ohm

resistor

from

terminal6to

terminal

7,

a

jumper

from7to8to9,a

jumper

from

3to4,

and

a

50

ohm

resistor

between

terminals2and

3.

Ifapad

is

desired,

leave

the

jumpers

off

of

terrriinals

7-8-9

and

terminals

3-4

and

put

in

a

jumper

between

terminals3and

8

Unlimited

possibilities

of

terminations

can

be

produced

by

this

method

of

combining

the

resistances

inside

the

termination

box

with

external

resistance.

zao

MMF

1N34

INPUT

Li’

--

VERTICAL

looK

470

3

MMFT

30K

_________________

_______________

________

__________OSCtLLOSCOPE

DUND4

GROUND

FIGURE

17.

SCHEMATIC

OF

THE

HIGH

FREQUENCY

PROBE

-25-

-SIGNAL

TRACING

Figure

17

shows

the

arrangement

of

components

in

the

Simpson

High

frequency

Probe,

No.

10-890025,

which

is

availabletoowners

of

the

Model

479

at a

nominal

cost.

Connect

this

probe

to

the

SIGNAL

INPUT

of

the

Model

479

to

trace

the

signal

through

an

f-m

or

television

receiver.

The

probe

is

essentially

a

high

frequency

detector

and

it

may

be

used

to

pickup

the

modulationonthe

signalfrom

any

part

of

the

system

where

high

frequencies

exist.

To

trace

a

signal

through

the

sound

channels

of

a

television

receiver

or

through

an

f-m

receiver,

connect

the

OUTPUT

cable

to

the

antenna

terminals

of

the

receiver

and

set the

A.M.

GENERATOR

to

the

sound

carrierfrequencyof

the

channeltowhich

the

re

ceiveristuned.

Rotate

the

SIGNAL

switch

to

MOD.

R.F.

Connect

the

high

frequency

probe

cable

to

the

SIGNAL

INPUT

jack

and

the

ground

lead

to

the

receiver

chassis.

Starting

at

the

grid

of

the

converter,

the

signal

may

be

picked

up

at

each

successive

grid

and

plate

through

the

i-f

system.

The

400

cycle

modulation

pattern

should

in

crease

in

amplitude

as

each

succesive

stage

is

checked.

Inatelevision

receiver,

the

picture

system

may

be

traced

in

the

same

manner.

Set

the

A.M.

GENERATOR

to

the

picture

carrier

frequency

and

the

SIGNAL

switch

to

MOD.

R.F.

for

this

test.

Trace

the

signal

from

the

grid

of

the

converter

tube

through

the

video

i-f

amplifiers,

noting

the

increase

in

amplitude

of

the

400

cycle

modulation

patternaseach

successive

stageischecked.

Any

single

stage

may

be

checked by

connecting

the

OUTPUT

cable

across

the

in-

put

of

the

stage

with

the

A.M.

GENERATOR

settothe

proper

frequency

for

the

stage.

Contact

the

output

of

the

stage

with

the

high

frequency

probe.

TESTING

THE

AUDIO

AMPLIFIER

The

Model

479

containsa400

cycle

audio

oscillator

which

can

be

used

to

test the

audio

amplifier

section

ofareceiver.

Set

the

SIGNAL

switchatAUDlO.

Use

the

OUT

PUT

cable

and

the

SIGNAL

ATTENUATORS.

This

feature

is

of

special

value

when

tests

of

the

audio

amplifier

alone

are

desired.

To

test

the

audio

amplifier,

connect

the

OUTPUT

cable

across

the

discriminator

or

detector

output.

Turn

the

volume

control

of

the

receiver

to

its

fullonposition.

With

the

SIGNAL

switchinthe

AUDIO

position

and

the

SIGNAL

ATTENUATORS

and

the

os

cilloscope

vertical

gain

set

for a

satisfactory

indication,

connect

the

SIGNAL

INPUT

cable

across

the

various

points

to

be

checkedfromthe

demodulator

back

tothe

speaker.

Note

the

increase

in

signal

strengthaseach

successive

stage

is

checked.

Watch

for

distortion

of

the

sine

wave.

Setthe

SIGNAL

ATTENUATORS

as

low

as

possibletopre

vent

overloading

the

vertical

amplifiersofthe

oscilloscope

since

this

would

give

a

false

indication

of

distortioninthe

receiver.

For

the

best

indicationofthe

400

cycle

sine

wave,

set

the

oscilloscope

controls

to

produce

a

linear

sweep

which

will

show3or

4

complete

sine

waves

Internally

syn

chronize

the

wave

form

to

hold

it

steady

on

the

oscilloscope.

-26-

L4

C7

C

FIG.

18.

REAR

VIEW

OF

MODEL

479.

CASE

AND

SHIELDING

REMOVED

The

chassis

of

the

Model

479

is

mounted

into

its

case

with

18

screws

around

the

edge

of

the

front

panel.

Removing

these

18

screws

and2on

the

back

at

the

line

cord

hole

cover

will

allow

the

assembly

to

be

taken

out

of

the

case.

Figure

18

is

a

rear

view

of

the

Model

479

with

its

case

and

some

shielding

removed.

When

the

chassis

is

removed

from

the

case,

the

5Z4

rectifier

tube,

power

supply,

and

most

front

panel

controls

are

available.

Hole

plugs

over

the

internal

adjustment

points

in

the

A.M.

and

F.M.

Generators

may

be

removed

for

aligning

these

sections

while

the

shielding

is

in

place.

If

any

components

inside

the

generators

need

to

be

reached,

remove

the

18

screws

holding

the

back

shield

in

place

one

screw

is

behind

the

5Z4

and

take

off

the

panel.

Five

more

screws

hold

the

end

of

the

A.M.

Generator

section

in

place;

takeitoff

and

all

components

are

exposed.

The

F.M.

Generator

section

contains

four

tubes.

These

are;

V4,

a

6AK5

f-m

oscil

lator;

V5,

a

6C4

fixed

oscillator

140

mc;

V6,

a

6AK5

mixer;

and

V7,

a

6C4

used

for

f-rn

blanking.

The

A.M.

Generator

section

contains

three

tubes.

These

are:

Vi,

a

6C4

variable

r-f

oscillator;

V2,

a

6J6

crystal

oscillator

and

mixer;

and

V3,

a

66

audio

oscillator

/

-27-

and

beat

amplifier.

The

5.0

mc.

crystal

also

is

in

this

section.

All

tubesinthe

Model

479

should

be

checked

occasionally

to

insure

good

perform

ance.

The

Model

479

is

adjusted

carefully

at

the

factory

with

precision

standards,

but

due

to

the

nature

of

very

high

frequency

circuits

agingofparts

or

replacement

of

tubes

may

require

readjustmentofthe

oscillator

circuitstomaintain

the

original

accuracy.

Adjust

the

Model

479,

whennecessary,

against

its

own

crystal

calibratorasfollows:

1.

With

the

back

and

top

shields

removed

frombothoscillator

sections,

turn

the

POWER

switch

to

OPERATE

and

allow

the

Model

479

to

warmup

foratleast15minutes.

2.

Connect

the

VERT.

AMPL.

and

HORIZ.

AMPL.

cablestothe

vertical

and

horizontal

inputs

of

an

oscilloscope.

Set

the

Model

479

controlsasspecified

for

CAL

IBRATION

PROCEDURE

on

page

5

3.

Set

the

A.M.

GENERATOR

RANGE

switch

at

A,

SIGNAL

switchtoCAL.,

and

SIGNAL

ATTENUATORS

low.

Tune

the

oscillator

to

the

7.5

mc.

calibration

check

point.

4.

Adjust

C9

until

the

7.5

mc

zero

beat

indication

occurs

when

the

dial

pointer

indicates

exactly

7.5

mc.

.

Tune

the

oscillator

for the

3.75

mc.

calibration

check

point.

Adjust

L6

until

the

beat

occurs

when

the

dial

pointer

indicates

exactly

3.75

mc.

Recheck

the

7.5

mc.

setting

and

readjust

C9

if

necessary.

6.

Set

the

A.M.

GENERATORRANGE

switchtoB.

Tune

to

the35mc.

calibrating

check

point

and

adjust

C8

until

the

check

point

indication

occurs

when

the

dial

pointer

indicates

exactly

35

mc.Cl

.

Tune

to

the

15

mc.

calibration

check

point

and

adjust

L5

until

the

pointer

is

over

the

15

mc.

mark

on

the

dial.

Recheck

the

35

mc.

tuning

point.

Set

the

A.M.

GENERATOR

RANGE

switch

to

band

C.

Tune

to

the

120

mc.

calibration

check

point

and

adjust

C7untilthe

zero

beat

indication

occurs

when

the

dial

pointer

indicates

exactly

120

mc.

Tune

to

the

75

mc.

calibrating

check

point.

This

should

fall

exactly

at

the

dial

pointer

position

for

75

mc.

unless

L4

has

been

moved

physically.Ifnecessary,

loosen

the

two

set

screws

holding

L4

in

place

and

shiftL4in

or

out

to

obtain

the

beat

pattern

at

the

75

mc.

dial

indication.

Recheck

the

120

mc.

point.

Replace

the

top

shield

of

the

A.M.

Generator

if

it

was

removed

for

alignment

to

this

step.

tQ.

Connect

a

crystal

diode

such

as

a

1N34

between

the

center

contactsofthe

OUTPUT

and

SIGNAL

INPUT

jacks.

L,i.

Set

the

SIGNAL

switchatCAL.

TunetheA.M.Generator

to

its

170

mc.

cal

ibrating

check

point.

Turn

the

SIGNAL

switch

to

UNMOD

R.F.

and

advance

the

SIGNAL

ATTENUATORS

to

10

and

MAX.

4r2.

Set

the

F.M.

GENERATORRANGE

switchatB,

F.M.

ATTENUATORSto

MAX.

and

10,

F.M.

SWEEP

to

0,

PHASING

to

0,

and

BLANKING

to

OFF.

1,.

Tune

the

F.M.

Generator

around

the

170

mc.

dial

mark

forazero

beat

in

dication

between

the

two

generators.

See

whether

the

dial

pointer

indicates

170

mc.

on

the

CENTER

FREQUENCY

dial

orifitisabove

or

below

the

mark.

-28-

Lt.

Set

the

A.M.

GENERATOR

RANGE

to

B,

SIGNAL

switch

to

CAL,,

and

SIGNAL

ATTENUATORpotentiorneter

to

6.

Tune

the

A.M.

Generator

to

its

70

mc.

calibration

check

point.

Turn

the

SIGNAL

switch

to

UNMOD.

R.F,

and

the

SIGNAL

ATTENUATOR

potentiometer

to

10.

i

Tune

the

F.M.

Generator

around

the

140

mc.

point

on

the

dial

forazero

beat

between

the

two

generators.

See

whether

the

dial

pointer

indicates

140

mc.

on

the

CENTER

FREQUENCY

dial,

or

if

itisabove

or

below

the

mark.

,.

1.

Adjust

C27

foracompromise

settingfor

the

170

mc.

and

140

mc.

frequency

positions

of

the

pointer.

Set

the

A.M.

GENERATOR

RANGE

switch

to

C,

SIGNAL

switchtoGAL.,

and

SIGNAL

ATTENUATOR

potentiometer

to

6.

Tune

the

A.M.

GENERATOR

to

the

240

mc.

calibrating

check

point,

Return

the

SIGNAL

switch

to

UNMOD.

R.F.

and

the

SIG

NAL

ATTENUATOR

potentiometer

to

10.

1&

Tune

the

F.M.

Generator

around

the

240

mc.

point

on

the

dial

for a

zero

beat

between

the

two

generators.

Zero

beat

should

occur

at

the

240

mc.

mark

on

the

dial

unless

the

rotor

for

L7

has

been

moved

on

the

tuning

knob

shaft.

If

it

needs

ad

justment,

tune

to

the

zero

beat

point

for

240

mc.,

loosen

the

allen

head

set

screw

on

the

shaft

coupler,

turn

the

tuning

knob

to

place

the

pointer

over

the

240

mc.

dial

mark

while

holding

L7

in

position,

and

then

tighten

the

alien

head

set

screw.

Recheck

the

170

mc.

and

140

mc.

indications.

19.

Set

the

SIGNAL

switch

at

CAL.

and

the

SIGNAL

ATTENUATOR

potenti

ometer

at

6.

Tune

the

A.M.

Generator

to

the

165

mc.

check

point.

Return

the

SIG

NAL

switchtoUNMOD.

R.F.

and

the

SIGNAL

ATTENUATOR

potentiometer

to

10.

20.

Tune

the

F.M.

Generator

around

the

165

mc.

mark

on

the

dial

forazero

beat

indicationonthe

oscilloscope.

21.

Remove

the

crystal

diode

from

the

OUTPUT

and

SIGNAL

INPUT

jacks.

Attach

the

cablestothese

jacks.

.

Connect

the

001

F’UI

cable

to

the

input01an

i-I

strip

tuned

br

a

response

pattern

in

the

vicinity

of

20

to

25

mc.

Connect

the

SIGNAL

INPUT

cable

to

the

grid

or

plate

of

the

last

i-f

amplifiertoobtainawave

form

similartofigure

15B

when

the

intermediate

frequencyistuned

with

the

F.M.

Generator.

23.

Set

the

A.M.

GENERATOR

RANGE

switch

to

B,

SIGNAL

switch

to

CAL.,

and

SIGNAL

ATTENUATORS

to 0

and

Xl.

Tune

the

A.M.

Generator

to

the

25

mc.

cal

ibrating

check

point.

Set

the

SIGNAL

switch

at

UNMOD.

R.F.

24.

Set

the

F.M.

GENERATOR

RANGE

switch

at

A,

F.M.

ATTENUATORS

at

MAX.

and

10,

and

F.M.

SWEEP

at

10.

Tune

G34

until

the

maximum

i-f

response

is

seen

on

the

oscilloscope.

Note

that

several

response

curves can

be

seen

with

very

little

rotation

of

C34.

Tune

to

the

largest

response.

25.

Advance

the

SIGNAL

ATTENUATORS

untilamarker

can

be

seen

on

the

response

pattern.

Keep

them

set

as

low

as

possible

with

the

marker

just

visable.

26.

Reduce

the

F.M.

SWEEP

gradually

toward

zero.

Adjust

C34

to

keep

the

marker

on

the

trace

as

long as

possible

while

reducing

the

sweep

control.

This

is

a

rough

adjustment

of

C34.

27.

Remove

the

OUTPUT

and

SIGNAL

INPUT

cables

and

connect

the

1N34

-29-

between

the

center

jack

contacts.

Turn

the

SIGNAL

switch

to

CAL.

and

SIGNAL

ATTENUATOR

potentiometer

to

6.

Set

the

AJ’S&

GENERATOR

RANGE

switch

to

C

and

tune

the

A.M,

Generator

to

the

170

mc.

check

point.

Turnthe

Signal

switch

to

UN

MOD.

R.F.

and

the

SIGNAL

ATTENUATOR

potentiometer

to

10.

28.

Set

the

F.M.GENERATOR

RANGE

switchtoB

and

F.M.

SWEEP

at

0.

Tune

the

F.M.

Generator

for

a

zero

beat

indicationat170

mc.

29.

Set

the

SIGNAL

ATTENUATOR

potentiometer

at

6,

the

SIGNAL

switch

at

CAL.,

and

the

A.M.

GENERATOR

RANGE

switchatB.

Tune

the

A.M.

Generator

to

the

30

mc.

calibrating

check

point.

Setthe

SIGNAL

switchatUNMOD.

R.F.

and

the

SIGNAL

ATTENUATOR

potentiometer

to

10.

30.

Set

the

F.M.

GENERATOR

RANGE

switch

at

A.

Very

carefully

adjust

C34

for

a

zero

beat

indication.

This

isafine

adjustment

and

should

require

onlyaslight

touch-up

adjustment

on

C34.

Caution:

this

fine

setting

should

require

no

more

than

30

of

rotation

of

C34.

If

it

appears

to

need

more,

go

back

to

step

19

and

repeat

the

steps

more

carefully.

31.

Set

the

SIGNAL

switchatCAL.

and

the

SIGNAL

ATTENUATOR

potentiometer

at

6.

Tune

the

A.M.

Generator

to

the

35

mc.

calibrating

check

point.

Turn

the

SIGNAL

switch

to

UNMOD.

R.F.

and

the

SIGNAL

ATTENUATORS

to

10

and

MAX.

32.

Observe

the

oscilloscope

while

rotating

the

F.M.

tuning

knob.Aconstant

zero

beat

should

occur

between

the

35

mc.

from

the

A.M.

Generator

and

140

mc.

from

the

fixed

oscillator

regardlessofthe

position

of

the

pointeronthe

CENTER

FREQUENCY

dial.Ifthis

situation

does

not

exist,

the

fixed

oscillator

is

tuned

to

an

incorrect

fre

quency.

Go

back

to

step

19

and

repeat

the

140

mc.

oscillator

adjustment.

33.

Remove

the

crystal

diode

and

replace

all

shielding.

The

Model

479

oscil

lators

are

now

aligned

within

the

close

tolerancestowhich

they

were

adjusted

when

it

was

manufactured.

SWEEP

ADJUSTMENT

The

f-m

sweep

motor

is

factory

adjusted

to

provideasweep

bandwidth

of

15

mc.

when

operated

on

110

volts,

60

cycles,

and

with

the

F.M.

Generator

tuned

to

160

mc.

and

the

F.M.

SWEEP

control

at

10.

Operation

on

other

line

voltages or

at line

fre

quencies

other

than

60

cycles

will

require

re-setting

of

the

sweep

limiter

adjustment,

R55.

Use

the

fo1loving

procedure

to

adjust

R55.

1.

Turn

the

POWER

switch

of

the

Mode1479

to

OPERATE

and

allow

15

minutes

for

th&utht

to

war,n

up.

Connect

the

VERT.

AMPL.

and

HORIZ.

AMPL.

cables

to

the

vertical

and

horizontal

inputsofan

oscilloscope.

Set

the

function

switchofthe

oscillo

scopetoutilize

the

60

cycle

sine

wave

sweep

for

horizontal

deflection.

Connectacrystal

diode

such

as

a

1N34

between

the

center

colitactsofthe

OUTPUT

and

SIGNAL

INPUT

jacks.

2.

Setthe

A.M.

GENERATOR

RANGE

switchto

C,

SIGNAL

switchto

CAL.,

and

SIGNAL

ATTENUATORS

to6and

MAX.

Tune

the

AM

Generator

to

the

160

mc.

check

paint.

Turn

the

SIGNAL

switch

to

UNMOD.

R.F. and

the

SIGNAL

ATTENUATOR

poten

tiometer

to

10.

3.

Setthe

F.M.GENERATORRANGE

switchto

B,F.M.ATTENUATORSto

MAX.

and

10,

and

F.M.

SWEEP

to

0.

Tune

the

F.M.

Generator

to

zero

beat

at

160

mc.

-30-

4.

Turn

the

F.M.

SWEEP

to

10

and

the

PHASING

controltoa

position

which

produces

an

open

oval

or

circle

on

the

oscilloscope.

Note

the

two

markers

on

the

pattern.

Reduce

the

SIGNAL

ATTENUATORS

to

as

low

a

setting

as

will

still

keep

the

markers

visable.

5.

Rotate

the

A.M.

Generator

tuning

knob

and

note

that

the

two

markers

move

around

the

trace

until

they

join,

produce

a

zero

beat,

and

then

disappear.

Read

the

frequency

on

the

A.M.

Generator

dial

at

the

point

where

the

markers

zero

beat.

6.

Rotate

the

A.M.

Generator

tuning

knob

in

the

opposite

direction

until

the

markers

move

to

the

opposite

sideofthe

trace

and

join

and

zero

beat

again.

Read

the

frequency

on

the

A.M.

Generator

dial

again

at

this

zero

beat

point.

7.

The

frequenciesinsteps5,and6identify

the

limit

frequencies

toward

which

the

F.M.

GENERATOR

is

being

swept.

These

should

have

a

difference

of

15

mc.

If

they

do

not,

adjust

R55

to

correct.

Caution:

Do

not

adjust

the

sweep

beyond

the

15

mc.

bandwidth

point.

The

motor

reaches

the

limit

of

its

swingalittle

beyond

this

point

and

will

be

damaged

if it

is

allowed

to

strike

the

stopsfor

any

considerable

periodoftime.

Should

your

Model

479

fail

to

give

satisfactory

service

due

to

reparable

damage,

it

can

be

returned

to

the

factory

for

repairs.

Always

accompany

any

equipment

sent

in

for

repair

with

a

statement

indicating

where

the

trouble

is;

for

example,

"A.M.

Gen

erator

dial

binds

"or

"F.M.

Generator

intermittent

after

Z

hours

of

use",etc.

This

will

facilitate

repairs,

keep

your

billtoa

minimum,

and

insure

that

the

fault

will

be

corrected

when

you

receive

your

Model

479

again.

WARRANTY

SIMPSON

ELECTRIC

COMPANY

warrants

each

instrument

and

other

articles

of

equipment

manufactured

byitto

be

free

from

defects

in

material

and

workmanship

under

normal

use

and

service,

its

obligationunder

this

warranty

being

limited

to

making

good

at

its

factory

any

instrument

or

other

article

of

equipment

which

shall

within

90

days

after

deliveryofsuch

instrument

or

other

articleofequipment

to

the

original

purch

aser

be

returned

intact

to

it,orto

one

of

its

authorized

service

stations,

with

trans

portation

charges

prepaid,

and

which

its

examination

shall

disclose

to

its

satisfaction

to

have

been

thus

defective;

this

warranty-being

expressly-in

lieuofall

other

warranties

expressed

or

implied

and

of

all

other

obligations

or

liabilities

on

its

part

and

SIMPSON

ELECTRIC

COMPANY

neither

assumes

nor

authorizes

any

other

persons

to

assume

foritany

other

liability

in

connection

with

the

saleofits

products.

This

warranty

shall

not

apply

to

any

instrument

or

other

article

of

equipment

which

shall

have

been

repaired

or

alteredoutside

the

SIMPSONELECTRIC

COMPANY

factory

or

‘authorized

service

stations

norwhichhas

beensubjecttomisuse,

negligence

or

acci

dent,

incorrect

wiring

by

others,

or

installation

or

use

not

in

accord

with

instructions

furnishedbythe

manufacturer.

-31-

PARTS

LIST-MODEL

479

CIRCUiT

REFERENCE

Cl

C2 C3 C4 CS C6 C7 C8 C9

do Cl’ C1z C13 C14 C15 C16 C17 C18 C

19-26

C

19-26 C27 C28 C29 C30 C31

C32 C33

C34 C35

C36 Q37 C38 C39 C40 C41 C42-50 C42-50 C51

C52 C53 C54 C56 C57 C58 C59

C60 Fl 11

r3

Li LZ

SI

MPSON

PART

NUMR

ER

1-113911 1-113899 1-1

13911 1-113899 1-113913 1-113898 1-114659

1-113891 1-1

13891 1-113916 1-113855 1-113855 1-113895 1-113978 1-113855 1-113902 1-113855 1-113855

1-I

!4b45

10-890126

1-113915 1-113912 1-113854 1-113854

1-

113854

1-113893 1-113893

1-113920 1-113912 1-113854 1-113854 1-1

13S

1-113913

1-113913 1-113854 1-114643

10-890

127 1-113912 1-113912

1-113903 1-113963 1-113913 1-113913 1-113898 1-113898

1-113855 1-112911 1-113982 1-113983 1-113983 1-113983

10-890040

Capacitor

8ZOOuuf

mica

Capacitor

.OSuf

400

V.

paper

Capacitor

8ZOOuuf

mica

Capacitor

.OSuf

400

V.paper

Capacitor

S000uuf

ceramic

Capacitor

.O2uf

400Vpaper

Capacitor

4.5-Z5uuf

trimmer

Capacitor

2.2-Z0uuf

trimmer

Capacitor

2.2-Z0uuf

trimmer

Capacitor,

2

gang

tuning

Capacitor,

Z000uuf

ceramic

Capacitor.

Z000uuf

ceramic

Capacitor,

l0uuf

ceramic

Capacitor,

47Ouuf

ceramic

Capacitor,

Z000uuf

ceramic

Capacitor,

0.luf

400

V.

paper

Capacitor,

Z000uuf

ceramic

Capacitor,

Z000uuf

ceramic

Capacitors,

l000uuf

feedthrough

Assembled

on

one

plate

Capacitor,

2-6uuf

trimmer

Capacitor,

lOOuuf

ceramic

Capacitor,

2ZOuuf

ceramic

Capacitor,

2Z0uuf

ceramic

Capacitor,

ZZOuuf

ceramic

Capacitor,

3.3

uuf

ceramic

Capacitor,

3.3

uuf

ceramic

Capacitor,

3.5-l5uuf

trimmer

Capacitor,

lOOuuf

ceramic

Capacitor,

2ZOuuf

ceramic

Capacitor,

ZZOuuf

ceramic

Capacitor,

Z000uuf

ceramic

Capacitor,

S000uuf

ceramic

Capacitor,

S000uuf

ceramic

Capacitor,

ZZOuuf

ceramic

Capacitors,

l000uuf

feedthrough

Assembled

on

one

plate

Capacitor,

lOOuuf

ceramic

Capacitor,

lOOuuf

ceramic

Capacitor,

0.ZSuf

400

V.

paper

Capacitor,

40-1

Ouf

350V.D.C.

electrolytic

Capacitor,

S000uuf

ceramic

Capacitor,

S000uuf

ceramic

Capacitor,

.OZuf

400

V.

paper

Capacitor,

.02u1

400

V.

paper

Capacitor,

Z000uuf

ceramic

Fuse,2amp

3AG

Jack,

OUTPUT

Jack,

SIGNAL

INPUT

Jack,

VERT.

AMPL.

Jack,

HORIZ.

AMPL.

Line

Filter

Line

filter

-32-

PARTS

LIST

-

MODEL

479

CIRCUIT

SIMPSON

REFERENCE

DESCRIPTION

10-890034

L4

NC"

10-890033

L5

"A"

10-890031

L6

"B"

10-890032 10-890028

L8

10-890030

L9

10-890039

Ml

22-302118

Ri

1-113947

R2

1-113933

R3

1-113959

R4

1-113949

R5

1-113949

R6

1-111689 1-113921

RB

1-113949

R9

1-113048

1A

1

ll2flIZO

LL.J7/

Ru

1-113959

R12

1-113943

R13

1-113960

R14

1-113960

R15

1-113945

R16

1-111671

R17

1-113956

R18

1-111689

R19

1-113979

R20

1-113048

R21

1-111671

R22

1-111689

R23

1-111940

R24

1-113943

R25

1-113961

R26

1-113949

R27

1-111693

R28

1-113941

R29

1-113941

R30

1-113958

R31

1-113949

R32

1-113927

R33

1-113877

R34

1-113923

R35

1-111684

R36

1-113923

R37

1-111684

R38

1-113923

R39

1-111684

R40

1-113923

R41

1-111684

R42

1-113922

R43

1-113947

R44,45

1-113880

PART

NUMBER

85uh

choke

coil

Oscillator

coil,

A.M.

Band

Oscillator

coil,

A.M.

Band

Oscillator

coil,

A.M,

Band

Coil

assembly,

F.M.

tuner

Oscillator

coil,

l4Omc.

Filter

choke,

Power

supply

Sweep

motor

assembly

Resistor,

56K

1/2

W.

10%

Resistor,

33K

1/2W.

10%

Resistor,

22K

2W.

10%

Resistor,

lOOK

1/2W.

10%

Resistor,

100K 1/2w.

10%

Resistor,

1K

1/2W.

10%

Resistor,

47

ohms

i/zw.

10%

Resistor,

100K

1/2w.

10%

Resistor,

6.8K

1/2W.

10%

t

tP

UT

1

nat

fl.0£0

k’.J

S

i_sfli_s

7Y.

-

.1.U/0

Resistor,

22K

2W.

10%

Resistor,

18K

1/2W.

10%

Resistor,

33K

ZW.5%

Resistor,

33K

2W.

5%

Resistor,

33K

1/2W.

10%

Resistor,

10K

1/2W.

10%

Resistor,

8200

2W.

10%

Resistor,

1K

1/2W.

10%

Resistor,

7.5K

5W.

10%

Resistor,

6.8K

1/2W.

10%

Resistor,

10K

1/2W.

10%

Resistor,

1K

1/2W.

10%

Resistor,

100

ohm

1/2w.

10%

Resistor,

18K

1/2W.

10%

Resistor,

33K

2W.

10%

Resistor,

100K

1/2W.

10%

Resistor,

lOMeg

1/2W.

10%

Resistor,

2200

ohm

1/2W.

10%

Resistor,

2200

ohm

1/2w.

10%

Resistor,

12K 2W.

10%

Resistor,

lOOK

1/2w.

10%

Resistor,

150

ohm

1/2W.

5%

Potentiometer,

50K

Resistor,91

ohm

1/2W.

10%

Resistor,

750

ohm

1/2W.

10%

Resistor,

91

ohm

1/2W.

10%

Resistor,

750

ohm

1/2w.

10%

Resistor,

91

ohm

1/2w.

10%

Resistor, 750

ohm

1/2W.

10%

Resistor,

91

ohm

1/2w.

10%

Resistor,

750

ohm

1/2w.

10%

Resistor,

82

ohm

1/2W.

10%

Resistor,

56K

1/2w.

10%

Dual

Potentiometer,

2K

each

section

-33-

PARTS

LIST

-

MODEL

479

C

I

RCU

I

T

REFERENCE

0

E

Sc

RIPT10

N

St

MPSON

PART

NLJM8ER

R46 R47 R4

8

R49

R50 R5

1 R52 R53 R

54

R55

R56 R57 R58 R59 R60 R61 R62 R63

R117

Si

S2

S3 S4 S5 S6 Ti

T2 T3

vi

v2

V3 V4

vs

V6 V7 V8

Yl Yz

Resistor,

75

ohm

1/2w.

5%

Resistor,

750

ohm

1/2w.

10%

Resistor,

91

ohm

i/zw.

10%

Resistor,

750

ohm

1/2W.

10%

Resistor,

91

ohm

1/2W.

10%

Resistor,

750

ohm

1/2W.

10%

Resistor,

91

ohm

i/zw.

10%

Resistor,

75Oohm

i/2w.

10%

Resistor,

82

ohm

1/2W.

10%

Potentiometer,

i0ohm

Resistor,

6.8

ohm

2W.

10%

Potentiometer,

50

ohm

Resistor,

7K

20W.

Potentiometer,1Meg

with

switch

Potentiometer,

500K

Resistor,

10K

1/2W.

10%

Resistor,

330K

1/2W.

10%

Resistor,

150

ohm

1/2W.

10%

Resistor,

680

ohm

1W.

10%

Switch,

A.M.

GENERATOR

RANGE

Switch,

POWER

Switch,

SIGNAL

Switch,

F.M.

GENERATOR

RANGE

Switch,

F.M.

ATTENUATOR

Switch,

SIGNAL

ATTENUATOR

Transformer,

Plate

Transformer,

Modulation

Transformer,

Filament

Tube,

6C4,

A.M.

Oscillator

Tube,

T6.

Crystal

Oscillator8zMixer

Tube,

6Th

,

Audio

Oscillator

&

Beat

Amplifier

Tube,

6AK5,

F.M.

Oscillator

Tube,

6C4,

140

mc.

Oscillator

Tube,

6AK5,

F.M.

Mixer

Tube,

6C4,

Blanking

Tube,

5Y3GT,

Rectifier

or

5Z4

Crystal

Diode,

1N34

Crystal

5.0

mc.

.05%

Output

cable

with

termination

box

Oscilloscope

and

signal

input

cables.

Dial

Assembly,

A.M.

Dial

Assembly,

F.M.

Knob,

pointer

type

Knob,

tuning

type

1-114113 1-

111684

1-113923

1-1

11684

1-113923 1-111684

1-1

13923

1-111684

1-113922 1-113881

1-113955

1-113882 1-113919 1-113870 1-114153

1-111671 1-113950 1-113926 1-1

13929

1-1

13889 1-113883 1-113884 1-113885 1-1

13886

1-1

13886

10-890038 10-890037 10-890044

1-113975

1-1

13639

1

I

1-113611 1-113975

1-113611 1-1

13975

1-11467

1

1-113976

1-113852 1-113965

0-008370 0-008371

10-890027

10-890026

3-260

180

1-114050

-34-