Technical information

ManualsBrandsZenith ManualsTVs & monitorsC36C35

RADIO

RETAILING'S

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A/uie

SPARTON

SPARTON I. F.'T

MODEL

9-X

t72.5

172.5 75

{56

0 t7 2.5

t7 2.5 7rA 156

t72.5

{+P

172.5 75-L)( 156

t72.5

15 t72.5 75-B

156

f{ 172.5

{GP

172.5 76 15al

l+A t72.5

156 77 t1t

t72.5 56

172.5

t72.5

ftx

t72.5 57

{56 E0 155

16 t72.5

5E 156

El {56

t6AW. tt2.5

60 900

Et-a 156

t7 172.5

156 C2

156

172.5

62 156

63 156

172.5

6t 156 ta {56

2rx

172.5

61AX

156

EtX 156

25 t72.5

65 156

E6-X 156

2G.LW. t72.5

65-T 156 t01

156

172.5

66 {56

| t-X

t72.5

27-L

172.5 6GT

156 tt1

{56

27-X

t72,5 67

t15

3tt 1t6

tr2.t

6e t15

{75-A

155

2&X

112.5 70

t15 17rA]( 156

172.5 7t

155

178 t72.t

rGA

172.5 7t-B

{56

620-X 172,5

3GB

t72.5 72

t72.5

69t t15

tGc

172.5

tz-PQ

t72.5 75VA

t72.5

7t {56

75GX

172.5

3,.4

t72.5

?yA)(

156

ETGA

fl2.5

)rB

t72.5 7!BX

{56

67GX

tt2.5

t72.5 7a

t72.5

fThr

a-bort-wrvo

nprrhctaodync

connrtrr

t!q.9-!nod.b

opcrt- oa

intormcdlrto

frcqucncy

ol 900 k.c.

SPARTON

AC?, 62, 63.

Replacing

worn-out

friction

dial drives

Re-

move chassis

from set.

Remove

spring

tension

arrangement

from

shaft and

re-

place

with

brass rod or old variable

condenser

spacer

tube, drilled

fit

snugly over

shaft. File

brass

rod

down

until

is spool

shaped, similar to spools

used on sewing

ynachines.

This

may be

done

puttihg

the

rod

of spacer tube

small

bolt, rotatilg the bolt

in an

electric

drill

and

.holding

a file against

it. The

spool should now

covered

with

tape and metallic-xed

cement)

place.

should then be soldered to

the knob

shaft, easily temoved by

lift-

ing

the spring

before the tape is ce-

;'-Bras

dial

....

(poper

db/moyed)

Fig.l 0riginal-

Drive

mented

the

shaft. Remove the

paper

dial from

the

set

by taking

out the round

brass clip holCing

place.

Cut the

slotted

brass dist at A

& B, shown in

diagram; wrap

piece

dial

cabte around

the

drum

portion

of diat as shown in

Solder in

place

spot

marked

C and

wrap two turns

around spool

on shaft.

Splice or solder ends at

replace

paper

dial

and the

job

is done.

SPARTON

Bursts into full volunre lr,ith

volunre

control set lorv. Reolace

leal<v

cathode bypass.

SPARTON I6

Drifts, u'eak, rvhistles

check

the connectiolrs

the oscillator

coil.

One

conncction

is {astcne<l by :r

small

scres'

rvlrich sorks

loose

tirrre.

SPARTON 14. Intermittent recep-

tion, operation restored by

jaring

cabi-

net

. . .

This is

a common trouble which

may be attributed

generally

single

cause

in these models. The wire run-

ning from

the intermediate transformer

the 58

looses

some of its insulation

where it

passes

under the

shield-can.

The short is very

difficult to

actually

see and may

guarded

agaiost

with

short length of

spaghetti

the lead.

SPARTON

16. Internrittent

noise,

erratic

operation, become

.krcreasingly

noticeable if any

part

chassis

or tubes

tapped Due to looseness of

cou-

denser rotors on shaft. Rotor

hubs.are

cast. Drill and

tap, with a bottoming

tap,

the

hub

each rotor for

two

short

6/32 setscrews. Or solder one

end of

each hub to the shaft with a large,

hot

'iron

and spattertess flux. Also

desir-

able to

ground

center

of shaft

with

flexible

pigtail

ptace

of original

brush.

SPARTON

16.

Extreme motor-

boating

Insert

a static shield be-

tween

the

oscillator stator

and the ad-

jacent

r.f.

stator

the tuning con-

denser

gang.

This in no l/4y impairs

performance

as far

as selectivity and

sensitivity are concerncd. The

undesir-

able condition is

due to

r.f. from

the

oscillator

getting

the

second

detector,

blocking the

set through a.v.c.

action

and

releasing

periodically.

SPARTON 26.

Fading caused

mechanical

contacts,

all shiclds

and

ob-

vious

parts

apparently

tight . . . Dic-

cast rotors

of condenser

gang

frcquently

make high

resistance

contact

to shaft,

this resistence

rhowing up only

Wheatstone bridge

analysis. Drill

and

tap

holes

in each rotor

through to

gheft

and insert setscrcws.

SPARTON

36, Short-lived vibrators

Connect

.01 mike, 1600 volt conden-

ser across

secondary winding

power

transformer in

the eliminator unit.

In-

stall

the condenser in all sets serviced

precautionary

measure,

adding

cost

to bill.

SPARTON 36

Vibrator burns

out . .connect a .01

mfd 1600 volt

condenser

across second-

ary

winding

power

transformer.

SPARTON €. No a.v.c. action

. . . Try replacing a.v.c. 37 first. If

this does not cure trouble

check the 160

ohm

rcsistor

connected to r.f. cathodes,

chokes and

ground,

SPARTON 40.

B-battery ddatl, or

heavy

cnrrent

drain on

eliminator

Replace

shorted I mfd.

condenser used

to by-pass screen

438 power

tube.

SPARTON 57

A.C.. D.C.

Dead,

plate

voltage

all

tubes

. .

open 1000

ohm molded

resistor

located

between filter

unit

and olate of

6D6.

SPARTON

6t.

62.

Tunable

squeal all

over

dial

these

a.c.-d.c.

modets

. . Check 5 mike, 165

volt

section

of 6lter

condenser

block for

leakage.

present,

cut

green

lead

and

replace

with 8 mike. 200

volt

unit.

SPARTON 6I, 62

'I'he

shielde<l

grirl

lead rruming bc-

tn'eerr tlre 2575 irn<l 43

oftcn shorts

clue to

insulatiotr

clurrrbling flonr hcat

e-Kposurc.

Chcck

this

rvhcrr

scrvicirrg

thesc

urotlc'ls.

SPARTON 61, 62. Distortion, not

due

tci bad tubes or incorrect voltages

Check 5

mfd.

section

filter

condenser.

is across the speaker field

and

tapped

filter

choke

and

equipped with a

yet-

low

lead coming

out of the

block.

SPARTON 65,

66. Oscillation

See

if nretat

braid shielding

control-

grid

lead

of type 78 tubes, either

one,

has

becn

pushed

down accidentally

when removing

or installing tube

pack-

ing,

or changing tubes. If

so,

pull

shields

up to

their

full length.

SPARTON 65, 66. Improving

se-

lectivity

Removo L5

(part

A-

I l04t)

and install new

(part

A-

11535). Rembve

(part

A-10973)

and

install new

(part

A-11474). Connect

one

condenser of C3 across

primary

and

connect

other condenser across sec-

ondary of L5. Remove

resistor

R-ll

(part

8-5243-34)

and

install

part

B-

5458-1 2,200

ohm., .25 watt unit.

Re-

move resistor R-I5

(part

8-5458-33) and

install

part

8-5458-31

(30,000

ohm)

.25

watt unit.

SPARTON 67, 68, 691.

Vibration

. Remove small

piece

of rubber in

middle of

rear

edge of

chassis

base'plate

and

place

small strips

one inch

mask-

ing

tape along

edges of base

plate,

pre-

venting

plate

from

vibrating.

against

chassis

frame.

Stick

one end of tape

top side of

plate

and

fold the other end

around so that it sticks to

the bottom.

Masking

tape is obtainable

at most

hard-

ware or

paint

stores.

SPARTON

Weak

or no leccption

tr:rce

lea<ls

connecting lo,'v cutls

o i

f . chokes to

coudenscr block.

Disconnect

learls fr-ou

block

and test

for

contirruit,r'irom the

now vacant

lug to cha.sis. A

reading

intlicatcs

this section shottecl. Replace

lr,ith

125 nrfd.

-1(X)

r'olt

unit.

SPARTON 69A,

794,

930,

931,

3ol.

Fourth

section of band-pass

selector,

just

preceding

r,f., sometimes cannot

tuned

resonance

with

first three sec-

tions,

producing

weak

reception

and

loss

selectivity. Give

first, second

and

third

selector trimmers

3 turns clock-

wise. This makes slightly

less tuning

capacity necesary for

given

frequency

and

fourth

section sclector

can

now be

adjusted for resonance Batance

set

customary manncr with oscillator

and

output meter and.

re-adjust kilocyclc

scale on dial by loosening

shaft

and re-setting.

Fis.?

After