Philco 16 Reference manual

PHILCO

RtO.

U.$.

PAT,

Off.

Price

change

effective

after

Sept.

15,

1933.

Service

Bulletin-No.

165-B

(This

Bulletin

Supersedes

Service

Bulletin

No.

165)

Model

16

TnE

PHILCO

RADIO

MonEL

16

is

an eleven-tube superhetero<lyne broadcast

and

short-wave receiver,

operating upon

alternating

current

and

employing the high-efficiency 6.3 volt tubes, automatic inter-

statiou noise suppression,

and

a frequency (wave-band) coverage

that

permits reception of

the

short-wave

(high-frequency) broadcast programs.

The

same superheterodyne circuit

is

used for all reception.

The

Receiver is equipped with a five-point wave-band switch.

The

ranges

are-

(1) 520 K. C.

to

1500 K. C. (3) 3.2

M.

C.

to

6.0

M.

C.

(2) 1.5

M.

C.

to

4.0

M.

C. (4) 5.8

M.

C.

to

12.0

M.

C.

(5) 11.0 M. C.

to

23.0 M. C.

The

Receiver employs a Philco

Type

77

tube

for first detector, a

Type

76

for oscillator, a

Type

78

for first

I.

F.,

a

Type

78 for second

I.

F.,

and

a

Type

37 for second detector.

The

automatic

interstation

noise suppression circuit uses a

Type

78,

the

first A.

F.,

a

Type

77.

The

driver (second A.

F.)

is a

Type

42;

the

class

"A"

amplification

is

accomplished with two

Type

42 tubes as triodes;

the

rectifier is a

Type

5-Z-3.

The

intermediate frequency

is

460 kilocydes.

The

power consumption of Model 16-122

is

130

watts;

of

Model 16-121, 120

watts.

'fable

1-Tube

Socket

Data*-A.

C. Line Voltage

115

Volts

Inter-

2nd

hi

hi.

2nd

Station

ht

A.

F.

Rectl·

Circuit

0,1.

01c.

I.F.

0,1.

Nol11

A.F.

(Drlv- Output

n,r

Supr. er)

Circuit

----

--

----

--

Type Tube

77

75

78

37

78 77

42

5-Z-3

----

--

----

------

--

Filament

Volts-F

to

F

........

0.3 6.3 6.3 6.3 0.3 0.3

fl.3

6.3 6.3 6.3 4.7

----

--

Plate

Volts-P

to

K

...........

220 53 225 230 0 1.8 130 220 340 340 400

----

--

Screen Grid Volt.o-SG

to

K

....

so

-

so

-1.8 1.8 220 340

340

-

------

--

----

Control Grid

Volts-CG

to

K

...

1.0 M 0 0 .2

UI

.4 .6

34

-

----

--

----

--

----

Cathode

Volts-K

to

F

........

4.2 1.9 2.2 2.5 0 0 0 0 0 0 -

• All of

the

above readinl!' were taken from

the

u!1der,i4e of the

cha~111,

ming test prods and leads with a suit-

able

A.

C. voltmeter

for

filament voltages, and a h,gh-re,nstance multi-ran11e D. C. voltmeter

for

other readings.

The

Philco Model 048 All-Purpose Set Tester is highly recommended

for

this use. Volume control set

at

maximum

nnd stn.tion .,eJector

turned

to

low frequency

end;

interstation

noise suppression circuit J><?lentiometer

turned

nil

the way

to

the right: and toggle switch (interstation nmse suppression circuit)

in

"0:,./

..

(''S")

position. Reuding•

taken with a

plu11-in

adapter

will

NOT

be

satisfactory.

NOTE-These

values

arefor Model 16-122.

Model 16-121 uses a

Type

80

Rectifier

Tube.

SeeNote,page

4,

at

end of Replace-

ment

Parts

Li!t.

Table

2-Power

Transformer

Data

TYPE 1-2

TU8E

TY•E4:1.

TUU-fc:==~

n,r.u

TUIE

TYPE 5·1.·3

TVPE

77

TUBE TUBE

TYPri

37

TUIE

TYPE711

TUIE

TYPE70

TU&E

~Fl~.

1-Top

View

of

Chassis,

Showing

Tube Locations

and

Major

Puts

~

~~}

Sockets

c-~

78

} Sockets

·ua1

Terminal

1-2

3-5

0-7

8--10

4

9

A.

C.

Volta

Circuit

Color

105-125

Primary

White

6.3 Filament Black

5.0 Filamentof 5-Z-3 Blue

800 Plates of 5-Z-3 Yellow

-Center

Tap

of

3-5

Black-Yellow

Tracer

-Center

Tap

of

8--10

Yellow-Green

Tracer

g

42

Socket

,

~

5-Z-3 Soeker

Terminal Arrangement

of

Tub,

Sock1to

Viewed

from

Und1rold1

of

Chassis

1 3 4

I

oO

O S

o~

All

SWITCH

SECTIIMS

SHOWN

IN

,os1TION

1fil

/

Flt, 2-Schtmatlc Wlrlni Dlairam

J.F.=460

K.C.

GmNlWNIT[

iSrl:fil:f

t},tb.

fJ

,,.

TO

CAN

@

INTERNAL

CONNftTIONS

FILHR

CINIENSER

~ANK

00

(P

"'1

~

-

r:i

(P

c:,

=

-

(P

<"1-

.....

::::s

z

0

.

-0

:c

r-

0

No.

165-B PH I LCO

Service

Bulletin

Page 3

ANTENNll.

GROUND

Fir.

3-Bottom

View

of

Chassis,

Showin,i

Parts,

and

Position

of

Compensatin&

Condensers

Located

Under

Chassis

~A.

'""·~""-W/1.VETRAP

IST I.F. IITI.F.

~~l'IARY

@@5

.

2••1.R~2•0l.F.

SECONDARY

~

@

PRIMARY

3"DI.F.

)RD

I.F.

SfCONDAA~PRll'IAIW

VOLUME

CONTROL.

AND"

ON·OFF"SWITCH

4

~

3

~

2

~

l

STATION

SELECTOR

H.F.ANT.

L.F.ANT.

RANGE

2.

TOME

CONTROL

Fir.

4-Position

of

CompenutinR

Condensers

Located

Abov"

Chusis

NOTE:

DO

NOT

ATTEMPT

TO

ADJUST

the

compensating

condensers

mounted

upon

sections

3

and

'I

of

the

tuning

condenser.

These

com pcnsatinrr

condensers

are

carefully

adjuste<I,

and

scaled

at

the

factory.

Inability

of

a suitable

radio

receiver

to pick

up

signals

upon

the

shorter

waves

(higher

frequencies)

frequently

can

be

traced

to

the

aerial

itself.

A

relatively

short,

but

efficiently

designed,

aerial

will

give

better

results

on

the

short

wo.ves

than

one

which

has

a Jong

and

involved

lead-in.

Extreme

care

should

be

exercised

in

the

installation

of

the

Model

16,

that

it

may

have

every

opportunity

to

bring

in

all

the

frequencies.

Instruction

should be

given

the

customer

in

tuning

in

the

shorter

waves,

which

are

characteristically

difficult

for

a novice.

Attention

should

be called

to

the

time-difference

existing,

that the listener

may

not

listen

at

such

hours

as a

desired

station

is

n-ot

transmitting.

Much

good will be accomplished

by

a

thorough

instruction

of

the

customer.

Philco

distributors

are

prepared

to

supply

special

aerial

equipment,

especially

designed

for

reception

of

the

short

waves.

ADJUSTING MODEL

16

(Refer

to

Service

Bulletin

No.

16S-A)

These

receivers

are

adjusted

accurately

at

the

factory

prior to shipment.

Under

normal conditions

it

is

not

neccs·

sary

to

readjust

the

compensating

condensers.

If

such

adjustment

becomes

necessary,

it

should

not

be

attempted

without

first

making

sure

that

proper

instructions

and

suitable

equipment

are

at

hand.

Philco

distributors

arc

in

•

position

to

supply

both.

The

Philco Model 048

All-

p,.rpose

Set

Tester

contains

a

variable-frequency

signal

generator

covering

all

frequencies

between 105

K.

C..

and

2000 K. C.,

nnd

is

highly

recommended

for

the

adjust-

ment

of

the intermediate

frequency

compen~atin.R:

con·

<lensers,

and

for the

adjustment

of

those

compensating

condensers

in

the

lower

frequency

circuits. Tlte Philco

Model

091

Siona/

Ge1<erator is recommended

for

the

higher

frequencies.

Refer

to

Service

Bulletin

No.

165-A

for

full-

instructions

upon

the

adjustment

of

Model

16

series.

CAUTION:

The

I.

F.

and

low

frequency

compensating

condensers only should he adjusted in emergencies.

Ex·

treme

care

should be exercised in ~djnsting the JI.

F.

circuits.

Page

4 PH I LCO

Service

Bulletin

No. 165-B

·-··

·-·

REPLACEMENT

PARTS

FOR

·MODEL

16

-

···.

. .

··,·---·-·

No.

on

Lisi

Figs. D11crlptlon · · Part

N·o.

PrlCI

CD

Wave Iland Switch

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

,

......

.

® Tuning Condenser Assembly

.........

:

..

42-1037 2.75

31-1039 4.50

@ Compensating Condemer

(Wave-trap)

..........

{ Wave-trap } 38

_5199

® Condenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5858

Part

of@)

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

.

CD

Compensating Condenser (Ant.; Broadcast

and Police;

Part

of @)

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

.

(H.F.

Bands)

......

32-1183

@ Resistor (Brown-Black-Orange)

..........

4412

@ Compensating Condenser (Range

3)

. . . . . . 04000-V

@ Condenser

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

30-1000

@ Compensating Condenser (Range 2; series) 04000-R

@ Compensating Condenser (Range

1;

series) 04000-R

@)

Condenser. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3615-L

@ Resistor (Green-Black-Red) . . . . . . . . . . . . . 5310

@ Condenser. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5886

@ Resistor (Brown-Black-Orange)

..........

4412

@ Oscillator Coil

(I-1.

F.)

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

32-1185

@ Conden~er. . . . . . . . . . . . . . . . . . . . . . . . . . . .

7301

.16

.20

.16

.20

.35

.16

.20

.25

.20

.35

@a

Resistor (Brown-Black-Orange)

..........

4412 .20

® Compensating Condenser

(Rangel;

Shunt) 0-4000-A .12

® Oscillator Coil (Broadcast and Police)

....

32-1184

@ Compensating Condenser (Osc.; H. F.;

Part

of®)

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

.

@ Compensating Condenser (Osc.; Police;

Part

of®)

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

.

@)

Resistor (Flexible Wire-wound; Green-

Black-Brown). . . . . . . . . . . . . . . . . . . . . . .

6977

@ Condenser. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5863

® Resistor (Green-Brown-Orange)

..........

4237

@ Compensating Cond'ser (1st,

I.

F. Primary) 31-6002

@ 1st, I. F. Transformer. . . . . . . . . . . . . . . . . . 32-1186

@ Compensating Cond'r (1st,

I.

F. Secondary) ~ilim@n

.20

.18

.25

@ Condenser

..

.

..

. . .

..

. . . .

..

. . . .

..

. 3615-AB .20

@)

Hesistor (Flexible Wire-wound; Orange-

Black-Brown) . . . . . . . . . . . . . . . . . . . . . . . 33-3010

.15

@a

Condenser

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

3615-BK .16

@ Resistor (Red-Black-Green)

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

5872 .20

@ Condenser

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

3615-BL

.16

@ Resistor (Brown-Green-Green) . . . . . . . . . . . 7009 .20

@a

Resistor (White-White-Orange)

..........

4411

.20

@ Resistor (Yellow-White-Yellow).... 4517

.20

® Compensating Cond'ser (2d, I.

F.

Primary) 31-6002 .35

® 2d,

I.

F. Transformer

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

32-1186

@ Compensating Cond'r (2d,

I.

F.

St"con<lary)

~ilim@)n

@ Condenser

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

3615-BK

.16

@ Resistor (Flexible Wire-wound; Orange-

Black-Brown) . . . . . . . . . . . . . . . . . . . . . . . 33-3010

@)

Pilot Lamp (Station Selector)

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

6608

@)

Shadow Tuning Meter. . . . . . . . . . . . . . . . . .

6497

@)

Pilot Lamp (Shadow Tuning Meter;

Part

of@))

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

.

.15

.12

2.25

@ Compensating Cond',er (3d,

I.

F. Primary) 31-6003 .35

@ 3d,

I.

F. Transformer

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

32-1188

,k~

~

·

Fl11.

· D11crlption Part

No.

Prlc1

@.

Compensating Cond'r (3d,

I.

F. Secondary) ~ilim@n

@ Condenser

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

3615-AS .25

@ Resistor (Part of @)

......

: .

..........

.

@)

Hesistor (White-White-Orange)

..........

4411

® Condenser

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

4519

@a

Condenser

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

4519

@)

Condenser (Double) . . . . . . . . . . . . . . . . . . . . 7296-G

@)

Resistor (Yellow-Black-Green)

..........

6010

@ Switch (Toggle); lnterstation Noise Sup-

pression Circuit. . . . .. . . . . . . . . . . . . . . . . 3253

@ Volume Control

and

"On-Off" Switch

....

33-5022

.20

.18

.20

.40

@)

Resistor (Orange-Red-Orange) . . . . . . . . . 5279 .

20

@a

Resistor

:orange-Orange-Yellow)

.....

6046 .20

® Condenser . . .

..

. .

..

. . . . .

..

. . . .

..

.

..

. 3903-J .20

@)a

Condenser

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

3903-J

.20

@)

Condenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4519 .18

@)

Condenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3615-AD .

20

@)

Resistor (White-White-Orange)

..........

4411

.20

® R.esistor (Violet-Black-Orange) . . . . . . . . . . 5385 .20

@)

Filter Condenser Bank. . . . . . . . . . . . . . . . . 30-4026 3.00

@)

Resistor (Brown-Blue-Yellow)

...........

5331 .20

@ Resistor (White-White-Orange) . . . . . . . . . .

4411

.20

@)

Condenser (Double)

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

6287-J

@

Input

Transformer

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

32-7057

2.25

@)

Resistor (Brown-Black-Orange) . . . . . . . . . . 3524 .

20

@)

Condenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3903-F .

15

@)

Output

Transformer

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

32-7052

1.50

@)

Voice

Coil and Cone

A!.!<embly

..........

36-3061 .

75

@ Speaker Field, Assembled with

Pot

(U-2). . 36-3088

@ Resistor (Brown-Black-Green)

..........

4409

@ Resistor (Wire-wound) . . . . . . . . . . . . . . . . . 33-3020

@ Resistor (Brown-Black-Green)

...........

4409

@ Condenser (Electrolytic) . . . . . . . . . . . . . . . 30-2003

® Resistor (Yellow-White-Yellow)

.........

4517

@ Condenser (Internal to.@)

.........

·

....

.

@ Tone Control . . . . . . . . . . . . . . . . . . . . . . . . . 30-4069

@)

Condensers (External to @) . . . . . .. . . .. . 7653-C

@ Voltage Divider Resistor (Wire-wound)

...

33-3021

@)

·Potentiometer (lnterstation Noise Suppres-

sion Circuit)

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

33-5015

@)

Resistor (Brown-Black-Orange)

..........

3524

.20

.30

.20

.70

.20

.16

.80

.20

@ Resistor (Brown-Orange-Orange)

........

6450 .35

@)

Filter Choke

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

32-7056

l.

85

@ Condenser

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

6287-F .12

® Condenser (Electrolytic). . . . . . . . . . . . . . . . 30-2011 1.

25

@ Condenser (Electrolytic) . . . . . . . . . . . . . . . . 30-2011 1.

25

@)

Power Transformer (50-60.--)

...........

32-7058 5.

00

@ Condenser (Double). . . . . . . . . . . . . . . . . . . . 3793-E .

20

® Resistor (Brown-Green-Orange) . . . . . . . . . 5718 .

40

Speaker

Socket.

. . . . . . . . . . . . . . . . . . . . 4957 .08

Tube Shield

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

28-1107 .10

Four-prong Socket.

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

7545 .08

Five-prong Socket.

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

7546

.10

Six-prong Socket

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

7547 .10

Knob

(Large)

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

27-4025

Knob (11:cdiurn)

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

03063 .08

Knob (Small)

..

. . . .

....

.

.. .. ..

. .

..

. . . . 03064 .

06

NOTE.-Model

16-121

uses

a

Type

SO

tube

in

lieu

of

5-Z-3.

Parts

used

in

the

16-121

chassis

that

differ

from

the

16-122

parts

above

listed

are:

@)

PowerTransformer(50-60.--)

...........

32-7080

4.50

Speaker

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

K-17

® Condenser (Electrolytic)

(8.0

Mfd.)

......

6706 1.50 Speaker Socket

Hole

Cover

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

7084

.75per

C

@ Condenser (Electrolytic)

(8.0

Mfd.)

......

746-1

1.25

Speaker Cable

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

L1632 .20

USE

PHILCO

REPLACEMENT

PARTS

AND

TUBES

FOR

EVERY

MAKE

RADIO.

GET

COMPLETE

CATALOG

FROM

YOUR

DISTRIBUTOR.

PHILCO

RADIO & TELEVISION CORPORATION

Septemller

1033

Printed in

U.

S.

A.

Service

Department

Sec. 1

"Cose

Histories"

of

Receiver Troubles

and

their

Remedies

PHILCO

14X,

14LZX-(Cont'd)

Inoperative

__

1)

failure

or

"open"

circuit

in

shadowcraph

(shadowcraph

(connected

in

"B"-plus

circuit

of

the

r-f

does

not

and

i-f

tubes

operate)

Intermittent

______

1)

snapped

coil

leads

at

lugs

of

01cillator

reception

coil

Insufficient

________

1)

small

antenna.

Increase

size of

antenna

shadowgraph

2)

weak

type

'44

tubes

in

r-f

and

i-f

stages

action

3)

increase

value

of

diode

detector

sec-

ondary-return

resistor

Shadowgraph

____

l)

receiver

circuits·

out

of

alignment

inoperative

on2)

defective

type

'6A7

tube

local

stations

No

control

of

____

1)

check

type

'37

tube

in

first

audio

stare

tone

Signal

drift

_____

1)

after

set

is

turned

on,

the

tuninr

of

the

station

"creeps"

for

as

long

as

30

to

60

minutes.

Replace

tension

spring

on

back

of

gang

condenser-use

new

type

Philco

spring

(part

No. 77760)

(

due

to

dial-

cueping)

Noisy

volume

___

1)

disconnect

end

of

control

that

goes

to

detector

and

from

this

detector

lead

con-

nect

a 300,000-ohm

%-watt

resistor

to

ground.

Also

from

this

lead

bridge

a

0.05

or

0.06-mfd. con.denser

to

the

dis-

connected

end

of

the

volume control.

This

removes

the

d-c

from

the

volume con-

trol

and

permits

quiet

operation

control

(

installing

a

new

control

only

a

tem-

porary

cure)

Motorboatinr

____

l)

eliminate

by

connecting

100,000-ohm

re-

1i1tor

from

first

audio

grid

to

chassis

sound,

Hum

Broad

tuninr

_____

i)

r-f

and

i-f

compensating

condensers

out

of

alignment

Whistling

__________

l)

compensating

condensers

out

of

adjust-

ment

2) move all

leads

adjacent

to

01cillator coil

further

away

from

it.

PHILCO

CT-14

Auto

Radio

Weak

reception

__

})

check

alignment-especially

of

antenna

1tction

of

tuning

gang.

To

improve

per-

formance,

move

the

lead

that

goes

from

~rst

grid

section of

gang

to

the

coil

away

from

all

other

leads

and

the

chassis

PHILCO

TH-14

lfodulation

hum

__

})

replace

conuenser

No.

1!

with

a ~-mfd.

at

hi,:h

volume

electrolytic

unit

PHILCO

15

Inoperative

________

l)

tuning

meter

No.

37

"open"

(indicated

by

narrow

shadow)

2) check

condenser

No.

13

(0.25-mfd.)

from

first

detector

plate

return

to

,:round

for

breakdown

3)

check

condenser

No.

16

(0.05-mfd.)

from

first

i-f

plate

return

to

ground

for

break-

down

(3-mfd., 0.5-mfd., 1-0.015-mfd.,

and

1-

1-mfd.)

4)

check filter

condenser

block No.

3S

5)

"open"

primary

of

input

transformer

No.

56

~) check No.

25,

couplin~

condenser

con-

nected

from

oscillator

plate

to

coil

(Cont'd)

PHILCO

15-(Co11t'c)

Intermittent

--1)

replace

the

200-ohm

oscillator

cathode

reception

resistor

and

the

0.09-mfd.

by-pass

con-

denser.

Use

a 0.1-mfd.

condenser

to

re-

place

the

odd-size 0.09-mfd.

unit

2)

replace

coupling

condensers

No. 44

and

No. 49 (0.01-mfd.

each)

in

first

and

second

a-f

stages.

Although

these

con-

densers

may

test

O.K.

it

is

best

to

re-

place

them

Distortion,

_________

})

connect a 0.25-rneg.

resistor

acro11

the

normal

volume control,

and

a 0.002-mfd.

condenser

between

the

plates

of

the

power

tubes

Weak,

"tinny"

at

hirh

volume

2) check condensers No. 48

(twin

0.25-mfd.)

for

breakdown.

Common

ground.

Ont

goes to

filter

resistor

of

first

audio

plate

supply,

the

other

to

filter

resistor

of

all

audio

grid

biases

3)

bn,akdown

in filter condenser block

No.

33

between

sectio11s.

Capacities

3-0.5-

mf

d.,

1-0.015-mfd.,

1-1-mfd.

4)

check

push-pull

input

transformer

No.

56

for

breakdown

(indicated

by

"fryin~"

noise)

Audio

whistle

----1)

replace

both

'47

push-pull

output

tt1b11

check

for

loose shield

cans

on

r-f

and

i-f

transfort.:.ers

Squealing,

--------1)

Noise.

Squealing

------1)

(intermittent

and

steady)

replace

condenser

No.

12

(0.09-mfd. con-

denser)

from

screens

to

ground.

Con-

denser

may

test

O.K.

but

may

be

inter-

No

:r;ero

Yolume

__

at

any

setting

of

volume

control

mittently

"open"

.

2)

replace

condenser

No.

13,

-(0.25-mfd.)

from

first

detector

plate

returns

to

ground.

Condenser

may

test

O.K.

but

may

be

intermittently

"open"

3)

replace

condenser

No.

31

(0.05-mfd.)

from

first

i-f

AVC

filter

resistor

to

ground.

Condenser

may

test

0.K.

but

may

be

intermittently

"open"

4)

replace

condenser

No. 26 (0.06-mfd.)

first

i-f

plate

return

to

ground.

Con-

denser

may

test

O.K.

but

may

be

inter-

mittently

"open"

A

VC

Condenser

No. 42 (0.00011-

mfd.)

connected

from

volume

control

to

rround

"Shadowgraph"

--1)

does

not

indi-

cate

on

weak

signals

replace

first

detector

and

i-f

tubes

Tuninr

con-

______

l)

faulty

spring

used

to

hold

drive

cable

under

tension.

Replace

with

imprond

spring

(part

No.

7776)

denser

slip-

pinr

PHILCO

16,

UB,

16X, 16RX-(C-O<l.es 121, 122)

Inoperatin

_______

l)

open

circuit

in

tuning

meter

No. 48

2) check

condenser

block No. 62. Common

goes

to

Cc:'.n;

condenser

A

(2-mfd.)

to os-

cillator

plate

filter

resistor;

condenser

B

to

tuning

metet';

condenser

C (0.6-

mfd.)

to

first

a-f

plate

supply

filter

re-

sistor;

condenser

D (0.5-mfd.)

to

screen

supply

of

first

a-f

tube;

condenser

E

(1-

mfd.)

to

screen

grid

supply

of

first

de-

tector

and

i-f

tubes

3)

check

condenser

No. 94 (0.05-mfd.)

from

first

detector

and

first

i-f

plate

supply

to

ground.

Faulty

condenser

here

indi-

cated

by

narrow

shadow

on

tuning

meter

4) check

for

breakdown

between

Hctions

of

condenser

black

No.

62. (Capaciti11

2-2-mfd.,

2-0.5-mfd.,

1-1-mfd.)

(Cont'd

over)

153

11

Case Histories

11

of

Receiver Troubles and their Remedies Sec. 1

PHILCO 1,,

1'B,

1'X,

1'RX-(Cod•

1%1,

12%)-(Ce,it'i)

Inoperatin

___

1)

wire

from

first

section

of

tuning

con-

(r-f

dead, f-f

denser

pulled too

tight

and

grounding

O.K.)

against

chassis

Inoperative

-------1)

(no

i-fj

high-voltage lead (

black

wire)

from

i-f

transformer

(first

facing

front

of

chassis) grounded.

This

does

not

effect

audio

2)

compensators in

top

of

i-f

can

grounded

to

can

Inoperative,

___

l)

Low !emsitivity

(possibly

short

wave

recep-

tion

comes

in

on

broad-

cast

band

setting)

check

contacts

on

band

switch.

These

contacts

may

shift

or

drop

out

complete-

ly.

This

m1:1.y

be

indicated

by

short

wave reception on

the

broadcast

band,

and

by

improper

tracking

of

the

oscil-

lator

check

for

intermittently

"open"

0.003-

mfd. condenser

No.

£0

Inoperative

at

__

l)

low

end

of

short-wave 2) check

for

intermittently

"open"

0.0007-

mfd. condenser connected

to

76

tube

band

Inoperative

_____

.:._1)

from

11

to

26 me.

Inoperative

be-

..

1)

, low 15

me

replace

condenser

from

lug

1 on

bottom

of

waveband

switch

to

ground

marked

with

orange

and

yellow

dots

with

one

of

the

"lug"

type

(value

700-mmfd.).

A

poor

connection

internally

in

the

pig-

tail

condenser stops oscillation

high

resistance

tuning

condenser

gang

rotor

contacts. Bond

rotor

to

tuning

condenser

frame

with

flexible

wire

pig-

tails

2)

tighten

screw

holding

the

bottom solder-

ing

lug

to

the

tuning

assembly

lnoperafr,e

at

___

1)

if

this

is due

to

failure

of 76

oscillator

to

function

at

the

high

frequencies,

first

try

a

new

76

oscillator

tube.

If

this

does

not

help,

change

the

500-ohm oscillator

cathode

resistor

to

a 300-ohm

unit

hich-freq.

end

of

broad-

cast

band

Intermittent

---1)

reception

(Tolume

drops

"open"

250-ohm

resistor

in

plate

circuit

of second

i-f

stage.

This

resistor

is

con-

tained

within

the

case

of

the

small

black

bakelite

condenur

for

this

stace

and

is

located

adjacent

to

the

2nd

i-f socket

to

very

low

level,

no

plate

voltage

on i-f 78

tube,

and

,:,:

..

"shadow-

..

, z-raph"

indi-

cation

wid-

ens)

Intermittent

____

l)

check 0.01-mfd.

tubular

audio diode-

coupling condenser connected between

bottom

terminal

of

volume

control

and

the

junction

of

the

two

diode load

re-

sistors

reception

(shadow-

.,

-·"~aph

oper-

atH

normal-

ly-)

2)

replace volume

control

3)

faulty

78

tube

(even

though

it

checks

O.K.)

4) replace coupling condenser

No.

59

(0.05-

mfd.) connected

from

first

a-f

to

second

a-f

tubes

5) check

transformer

No.

46

Intermittent

__

1)

reception,

check compensator condensers

No.

30,

39, 45 located

in

first, second

and

third

i-f

transformer

cans.

Fault

may

be

due

to

loose

rivets

or

dirt

between

plates.

Tap

cans

to

locate

trouble,

and

replace

assembly

Low 1en1itivity

(Cont'd)

154

PHILCO

1,,

1'B,

1,x,

URX-(Codes

121,

1%%)-(Cont'li)

Bass

distortion

-1)

(

treble

harsh)

(77

first

det.

and

two

i-f

check

for

reduction

in

value

of

10,000-

ohm

resistor

No.

83 connected

in

network

between noise

potentiometer

and

No.

91

15,000-ohm

resistor.

Replace

with

20-

w~tt

wire-wound

resistor.

Realign

re-

ceiver

78

screen

voltages

above

normal

after

set

warms

up)

Distortion

at

______

l)

replace 0.05-mfd. first

to

second

stare

low

volume

audio coupling condenser

No.

51

2)

check 10-mfd. electrolytic condenser No.

7S connected

from

high

voltage center-

tap

to

chassis

Distortion

at

___

l)

hich

volume,

Weak

"tinny-"

sirnal

check

for

breakdown

between sections of

condenser block

No.

62

(capacities

2-2-

mfd.,

2-0.05-mfd.,

1-1-mfd.)

Distortion

and

....

1)

check

grid-bias

voltage

for

the

driver

Hum

and

output

stages.

Lack

of

normal

bias

on

either

of

these

stages

usually

results

in

the

control

grids

of

the

42 tubes glow-

ing

red

(a

low-emission 42

tube

will

produce

the

same

result)

. Check

for

a

"leaky"

or

"shorted"

0.15-mfd.

grid

filter

?Y-pass con~ens~r

in

the

driver

stage

2)

1f

control-grid

bias

on 42

tubes

is low

or

absent,

check

secondary

return

of

push-pull

input

transformer

for

ground-

mg

to

the

case

or

the

laminations

of

the

transformer

internally.

Replace

trans-

former

3)

l.akage

of

the

paper

which

is

supposed

to

insulate

the

electrolytic

filter

con-

denser

from

the

chassis.

Either

one,

or

both, condensers

must

usually

be replac-

ed

4)

"leaky"

electrolytic condenser

No.

75. Re-

place

with

new

unit

Weak,

choked

----1)

reception

check

screen-grid

voltage

applied

to

77

first

a.f

tube

(should be

approximately

50

volts).

If

off,

replace

the

1-meg.

car-

bon

resistor

which

supplies

this

voltage

(with

tb

noise

sup-

pressor

tube

in

or

out

of

the

circuit)

How

to

tell

_______

1)

difference

b.-

tween

"fad-

ing"

and

"fre-

quency

drift"

Fa.dine

----------------1)

(

condensers

and

resistors

check

O.K.)

Fadinc-

--------1)

in all

cases

of

"apparent

fading"

of

sig-

nal,

shift

1·eceiver

tuning

5

or

10 kc plus

-then

minus.

If

this

restores

the

sig-

n~!,

the

trouble

is

not

due

to

fading

but

to

frequency

drift

which

has

occur-

red in some

part

of

the

receiver

(com-

mon causes

and

remedies

for

frequency

drift

in

various

models

of

receivers

list-

ed

further

on)

intermittent

open-circuit

in

the

third

i-f

transformer.

Replace

with

new

unit

if

defective

bakelite which holds

stator

of

oscillator

tuning

condenser

expands

or

contracts,

allowing set-screws

and

rivets

to

loosen.

This

causes

stator

to

shift

its

position

slightly

thereby

changing

the

oscillator

frequency. Remove

gang

condenser

and

tii-hten all

set-screws

and

rivets.

Realign

receiver

Intermittent

__

l)

secondary

of

first

r-f

transformer

has

fadinr

hirli-rHi1tance

connection (Cont'd}.

Sec. 1 "Case Histories••

of

Receiver Troubles and their Remedies

PHILCO

1',

1'B,

1'X,

1'RX-(CodH

1%1,

12Z)-(Co11t',f)

Fadinc

on

_______

1)

variable

tuning

condenser

imperfectly

crounded

to

chassis.

Bond

condenser

frame

to

chassis

with

heavy

flexible

pig-

tails

which

will

not

interfere

with

"float-

ing"

mounting

•hort-waye

bands

Oscillator

drift

2)

clean

the

rotor-shaft

contacts

S)

.tighten

all

screws

on

gang

condenser,

and

between

gang

condenser

and

chassis

4)

waveband

switch

not

grounded

perfect-

ly.

Ground

frame

of

waveband

switch

to

chassis

with

pigtails

5)

replace

fibre

insulator

on

high-frequency

compensating

condenser

with

new

and

thicker

type

Frequency

_________

l)

in

order

to

alleviate

frequency

drift

it

is

recommended

that

the

first

and

second

i-f

transformers

be

replaced

with

part

No.

32-1186,

using

compensating

con-

denser

assemblies

(Part

No.

91-6090),

with

shunt

condensers,

(Part

No.

30-1086)

connected

across

both

the

pri-

mary

and

secondary

sections.

The

third

i-f

transformer

should

be

replaced

with

Part

No.

31-1866

using

compensating

condenser

assembly

(Part

No.

31-6003),

no

shunt

condensers

being

used

drift

(due

to

i-f

drift)

Frequency

_______

l)

drift

(

due

to

dial-

creepinl')

Volume

un-

______

l)

controlled

Code

inter-

------1)

ference

Whi:stlinc

or

______

1)

1quealinc

(intermit-

replace

tension

spring

on

back

of

gang

condenser

-using

improved

Part

No.

77760

if

at

zero

volume

control

setting

and

with

the

QAVC

switch

in

the

S

position

the

volume

does

not

reach

minimum

or

zero,

replace

the

0.02-mfd.

condenser

in

the

78

QAVC

control-grid

circuit

with

a 0.01-mfd.

condenser

readjust

wave

trap

for

minimum

inter-

ference.

In

extreme

cases,

reduce

the

i-f

to

a

lower

value-say

440 kc.

The

high

and

low

frequency

compensating

condensers

of

the

oscillator

circuit

:should

be

readjusted

in

order

to

repro-

duce

the

correct

i-f

if

accompanied

by

.image

signal

check

0.05-mfd.

condenser

No.

15

for

"open."

Connected

from

first

detector

grid

re-

turn

to

ground

tently

or

:steady)

2)

check

0.05-mfd.

condenser

No.

48

from

second

i-f

plate

supply

filter

resistor

to

cround

3)

solder

pigtails

from

all

r-f,

i-f

and

oscil-

lator

transformer

shield

cans

to

ground

replace

loose

tuning

meter

bracket

4)

Hum

---·

----------1)

(in

early

replace

the

a-c

switch

jumper

from

switch

through

terminal

lug

mounted

on

condenser

at

back

of

set

with

shielded

wire

(with

the

shield

grounded)

:series)

Hum

----·--·--------1)

check

for

"open"

0.3-mfd.

condenser

No.

16

connected

across

filter

choke

Tone

impron-----1)

connect

a 0.006-mfd_ 400-volt

tubular

rnent

condenser

from

the

77

tube

plate

to

the

(

early

models)

tone-control

connection

Two

resonance

--1)

replace

shadowgraph

with

improved

part

peaks

indicat-

number

45-2021

ed

on

shadow-

graph,

Widening

of

shadow

upon

r•sonance

(Cont'd)

PHILCO

1',

1'B,

1,x,

1,RX-(Codea

121,

122)-(Cont'tl)

Choked

-----1)

open-circuited

2-mfd.

by-pass

condenser

B

in

condenser

block

2)

open-circuited

0.5-mfd.

first

audio

plate

by-pass

condenser

Noisy

reception

1)

defective

shadowgraph

bracket.

Replace

Motorboating

----1) check

for

"open"

section

in

condenser

sound

block No.

62

(capacitiH

2-2-mfd., 2-0.06-

(steady

or

in-

mfd.,

1-1-mfd.)

termittent)

PHILCO

16, 16-X, 16-RX

(Code

123)

See

also

the

Case

Histories

listed

for

Philco

1~

(Codes

121

and

122)

receivers

Inoperative

on

-.1)

high-resistance

contacts

in

waveband

S-W

band

switch.

Replace

wtih

new

switch

Intermittent

______

1)

intermittent

connection

between

coil

reception

lead

and

hook-up

wire

in

third

i-f

trans-

former

PHILCO

1',

16B, 16X

(Codes

125, 126)

Inoperative

______

l)

replace

0.05-mfd.

condenser

No.

!%

con-

n•cted

from

filter

resistor

of

r-f

ampli-

fier

plate

supply

to

ground

(open

shadow

on

tuning

meter)

2)

replace

twin

0.05-mfd.

condensers

No. 15

connected

from

each

side

of

shado-.r-

graph

to

ground

(open

shadow

on

tun-

ing

meter)

3)

check

1-mfd.

condenser

No-

79

connect-

ed

from

screen

grid

of

77

first

audio

tube

to

ground

•

4)

check

0.05-mfd.

condenser

No.

SI

con-

nected

from

filter

resistor

of

second

i-f

plate

supply

to

ground

5)

cheek

0.25-mfd.

condenser

No.

It

con-

nected

from

filter

resistor

of

first

audio

plate

supply

to

ground

Inoperative,

______

l)

check

contacts

on

band

switch.

These

contacts

may

shift

or

drop

out

complete-

ly.

(This

condition

may

be

indicated

by

Weak

reception

short

wave

reception

coming

in

on

the

broadcast

band

setting,

and

by

improper

tracking

of

the

oscillator)

Weak

nception

_})

check 0.003-mfd.

condenser

No.

11

con-

nected

from

ave

load

resistor

of

first

r-f

tube

to

ground.

Breakdown

indicated

by

inability

to

peak

on

broadcast

band

pad-

der

2)

check

for

"gassy"

5Z3

tube

Weak

reception._

1)

(intermit-

tently)

Weak

reception.

1)

No

plate

volt-

age

on

second

i-f

tube,

Wide

shadow-

graph

indica-

tion

Intermittent

_l)

reception,

check

compensating

condensers

No

. .JI

(first

i-f

primary),

No.

49

(second

i-f

primary),

No. 55

(third

i-f

primary).

Tapping

the

i-f

transformer

cans

will

usually

indicate

intermittent

condenser.

Replace

faulty

one

open-circuited

500-ohm

wire-wound

pig-

tail

type

second

i-f

tube

cathode

bias

rui:stor

open-circuitin~

0-06-mfd. cond•n:ser

con·

nected

between

the

junction

of

the

two

diode

load

resisto1·s

and

the

bottom

lur

of

the

volume

control

·

Very

weak

sig-

nals

(shadow-

graph

operates)

2)

open-circuiting

by-pass

condenser.

Trou-

ble

in

lead

contacts

3)

open-circuiting

250-ohm

resistor

a11em-

bly

blocks

in

i-f

plate

circuit

(Cont'd over)

155

11

Case

Histories'~

of

Receiver Troubles

and

their

Remedies Sec. 1

PHILCO

1',

168,

HiX

(Codes 1!5,

1!6)-(Cont'tl)

Distorted,

_________

l)

open-circuiting,

or

change

of

resistance

of

first

audio

tube

1-megohm

screen

re-

sistor

Intermittent

reception

2)

replace

0.05-mfd.

coupling

condenser

No.

75

connected between

first

and

sec-

ond audio

tubes

Distortion

at

_____

l)

breakdown

in

0.05-mfd.

coupling

con-

low Yolume

denser

No.

75 connected

between

first

and

second

audio

stages

Distortion

at

______

l)

"open"

0.25-mfd.

filter

condenser

No.

82

connected

in

plate

supply

circuit

of

77

hich

Yolume,

Weak

"tinny"

sicnals

first

audio

amplifier

'

Distortion

_______

l)

center-tap

of

push-pull

input

transform-

er

grounded

to

core

or

can

(Insulate

from

chassis

with

insulating

bushings

and

washers)

(crids

of

42

tubes

get

red

hot)

Distortion

_________

l)

leakage

between

insulation

and

chassis

of

first

filter

condenser

(screens

of

42

tubes

get

red

hot)

Whistling

or

_____

l)

insert

a 700-ohm

1-watt

carbon

resistor

in

series

with

the

plate

lead

of

the

78

r-f

tube,

and

remove

the

condenser

shown in

the

circuit

diagram

as

No.

2A

squealing

2)

check

for

"open"

twin

0.05-mfd. conden-

sers

No.

25.

These

are

connected

with

their

"common"

to

ground,

one

to

each

side

of

tuning

meter

3)

check

twin

0.0001-mfd. condensers

No.

61.-These

are

connected

with

their

"com-

mon"

to

ground,

one on

each

side

of

the

second

detector

grid

return

load

re-

sistor

4)

solder

pigtails

from

coil-mounting

screws

of

r-f,

oscillator

and

i-f

trans-

former

shield

cans

to

ground

lfotorboatinr

....

1)

check electrolytic

condenser

block No.

sound

rs,

red,

blue

and

blue 1-mfd. each,

plain

2-mfd. Common

negative

connects

to

can

Hum

_________________

l)

Hum

(intermit-

..

1)

tently)

check

for

"open"

0.3-mfd.

condenser

No.

97,

connected

across

filter

choke

check

for

"open"

8-mfd. electrolytic filter

condenser

No.

91

Dial sticks,

__

l)

excessive

pressure

exerted

by

felt

rests

Dial slipa

against

dial

2)

dial cable

worn

or

frayed

PHILCO

TH·U

Carrier

hum

_____

l)

replace

condenser

No.

lt

with

a 4-mfd.

at

hirh

electrolytic

unit

Yolume

PHILCO

17

SH

also Case

Histories

listed

for

Philco 15

Inoperatin

____

l)

check

for

"shorted"

0.05-mfd. condenser

No.

21

connected

from

oscillittor 11crHn

grid

to

ground

2)

"open"

tuning

meter

No.

ti

(indicated

by

narrow

shadow)

Inoperatin

with

1)

Yolume

con-

trol

at

mini-

mum

settinc

and

QAVC

switch

at

"on"

156

replace condenser 6 (

circuit

diacram)

with

a

O.Ol-mfd-0.002-mfd.

unit

(Cont'd)

PHILCO

17-{Cont'tl)

Intermittent

__

l)

check

for

"open"

first

audio

screen re-

reception,

sistor

Distortion

2)

check

for

increased

value

in

first

audio

1creen

resistor

3)

check

for

faulty

by-pass

condenser

in

rrid-return

of

oscillator

coil

4)

Intermittent

-----1)

reception,

check

for

faulty

r-f

transformer

check

the

2-mfd. section

of

the

filter con-

denser

block

by-passing

large

7,500-ohm

Cho

kine

wire-wound bleeder

resistor

2)

check

the

0.5-mfd.

condenser

units

by-

passing

the

70,000-ohm

resistor

in

the

1st

audio

plate

circuit.

They

are

mark-

ed B

and

C, respectively

Weak

reception

1)

cassy

type

'5Z3

tube

Choked,

__________

1)

1-meg.

carbon

resistor

in

the

plate

and

screen-grid

circuits

of

the

silencing

and

lit

a-f

tubes

has

increased

in

value,

thus

lowering

the

screen-grid

voltage

of

I::;t

a-f

tube

almost

to

the

cut-off point

Distorted

reception

Distortion,

___

l)

secondary

return

of

push-pull

input

transformer

grounded

to

metal

case or

laminations

internally

Hum

(

control-grids

of

output

42

2)

tubes

glow

leakage

between

electrolytic

filter con-

denser

cans

and

chassis-due

to

seepage

and

formation

of

oxides

at

the

bases of

the

condensers

red)

Hum

-----------------1)

(stronc

and

steady)

check

for

"open"

condenser

connected

across

speaker

field

Whistling

---------1)

(

intermittent

check

for

"open"

0.05-mfd. condenser

No.

21

connected

from

oscillator

screen

grid

to

ground

or

steady)

Apparent

_________

l)

check

for

loose

rivets

which

hold the

bakelite

insulating

panels

in

the

sides

of

the

tuning

condenser

sections, permit-

ting

the

statprs

to

shift

"fading"

due

to

freqµency

drift

in

receiver

PHILCO

17-X

Distortion,

____

1)

1st

tilter

condenser leakai-e between in-

sulation

and

chassis

Type

'42

1creens

get

red

hot

Hum

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

)

(stronc

and

steady)

check

for

"open"

condenser

connected

across

speaker

field

PHILCO

18

(Codes 122, 123)

Inoperatin

__

l)

control

grid

of

type

'75

tube

shortinr

to shield

can

2)

open-circuited

audio

coupling-condenser I

3)

"aborted"

tone

control

condenser

4)

check

first

i-f

primary

for

"open"

or

high-resistance

joints

5)

check AVC

coupling

condenser

for

"open"

or

"intermittent"

joint

6)

check

for

"shorted"

0.05-mfd. condenser

No.

12

connected

from

tuning

to

ground

(wide

shadow)

7) check

for

"shorted"

electrolytic

filter

condenser No.

40

(capacities

2-1-mfd.,

1-2-mfd.

(narrow

shadow)

8)

check

for

"open"

tuning

meter

'No. 63

(narrow

shadow)

.

9)

check

for

"shorted"

0.05-mfd. condenser

No.

20

connected

from

6A

7

tube

space

charge

grid

supply

filter

resistor

to

cround

10)

check

for

"shorted"

· 0.006-mfd. con-

denser

No.

4~

connected

from

plate

of

42

flrat

i-f

tube

to

ground

11)

check

for

"open"

primary

in

input

transformer

No.

41 (Cont'd)

Philco 16 Reference manual

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