Motorola 55C1, 55C2, 55C3, 55C4 Service Manual

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Page 1

Motorola

SERVICE

MANUAL

MODELS

SSC1

MAHOGANY

S5C2

WHITE

SSC3

MINT GREEN

SSC4

CLOVER PINK

CHASSIS

HS-456

GENERAL INFORMATION

TYPE - AC table model superheterodyne

receiver with plated

circuit chassis and loop antenna,, This receiver

has a self-contained

electric clock for automatically

controlling

the operation of the radio and the ap¬

pliance outlet.

TUNING RANGE - 535 to 16Z0 Kc

IF - 455 Kc

TUBE COMPLEMENT

1ZBE6 conv; 1ZBA6 IF amp; 1ZAT6 Det, AVC, 1st AF amp; 50C5 pwr amp; 35W4 rect.

POWER SUPPLY - Operates

from 117 volt, 60 cycle, al¬ ternating cur rent only. Power consump¬ tion 35 watts.

APPLIANCE

OUTLET - For use with 117 volt AC appliances

rated only at 1100 watts or less.

CLOCK - Duplex self-starting

electric clock. See Service

Notes for clock repair information.

INSTALLATION

OPERATING INSTRUCTIONS

Your Motorola is ready to operate when you plug it into any 117 volt, 60 cycle AC power line. Do not attempt to op¬ erate on DC as the clock motor will be damaged.

The clock is self-starting

and will operate when power is plugged into the power outlet. The sweep second hand will indicate when the clock is running.

set the hands on the clock to indicate the correct time, pull out AUTO¬ TIME SET knob (on rear of radio) and turn in a clockwise direction only. The self-starting

feature, in the event of a

temporary

electric power interruption,

will re-start the

clock but it will be necessary

correct for time lost by

means of the AUTO-TIME

SET knob.

Radio reception can sometimes

improved by revers¬ ing the power plug in power outlet. Try it both ways and leave it in position giving best reception.

A built-in loop antenna eliminates the need for an out¬

side antenna.

The antenna is somewhat directional,

there¬

fore, when receiving weak stations, reception may some¬

times be improved by rotating the receiver slightly in either direction.

MANUAL RADIO OPERATION

1. Turn OPERATION

SELECTOR

knob to ON. Allow a short period of time for tube warm-up. Z. Tune to desired station with the STATION TUNING knob.

3. Adjust volume control to desired level.

4. The radio will play until OPERATION

SELECTOR is

turned to OFF. AUTOMATIC

CLOCK-RADIO

OPERATION

1. Turn OPERATION

SELECTOR

knob to ON. Allow a

short period of time for tube warm-up. Z, Set the radio dial to the station you would like to hear

at any pre-determined

time, up to twelve hours in advance.

Adjust volume to desired loudness.

3. Push in AUTO-TIME

SET knob (on rear of radio) and

turn in a clockwise

direction

until RADIO ALARM SET

POINTER indicates the radio is to be turned on automati¬

cally.

4. Turn OPERATION SELECTOR to OFF and then to AUTO position.

Leave it in AUTO position.

5. The radio is now set to turn on automatically

time in¬

dicated by RADIO ALARM SET POINTER.

will continue

to play until OPERATION SELECTOR

turned to OFF.

BEDTIME CONTROL

The bedtime control feature is a timing device for turn¬

ing the radio and appliance off after any pre-set interval of time up to one hour. This feature allows you to listen to the radio while you are in bed, with the assurance

that it

will shut off automatically

after you are asleep. OrF

you

may turn off a lamp or appliance,

desired.

If appliance is not desired during the time the bedtime

control is in operation,

disconnect

appliance from recep¬

tacle.

TO SET BEDTIME CONTROL

Turn BEDTIME CONTROL knob clockwise.

The farther the control is turned, the longer the radio will play, up to a maximum of 60 minutes.

MOTOROLA,

INC.

4 54 5

AUGUSTA

BLVD.

CHICAGO

51,

ILLINOIS

Part No.

68P633301

Price 5 Cents

Printed in U.S.A.

Page 2

BEDTIME CONTROL AND AUTOMATIC OPERATIONS COMBINED

By combining the bedtime control and automatic radio

operation,

it is

possible to turn the radio off automatically

and to turn it on again automatically.

Thus, you may go to

sleep at night with music and be awakened with music again

the following morning.

TO USE THIS FEATURE,

SET CONTROLS AS FOLLOWS:

1. Push in AUTO-TIME

SET knob (on rear of radio) and

turn in a clockwise

direction

until RADIO ALARM SET POINTER indicates time radio is to be turned on automati¬ cally.

2. Turn OPERATION

SELECTOR to OFF and then to AUTO

position.

Leave it in AUTO position.

3. Turn BEDTIME CONTROL clockwise to any period of

time from 0 to 60 minutes.

4. Tune in desired station and adjust volume.

APPLIANCE

OPERATION

The APPLIANCE

OUTLET is located on the rear of the

set. .Coffee-maker,

heating pads, lamps, or any other elec¬

trical appliances which operate from 117 volt AC and do not

consume more than 1100 watts may be plugged into the AP¬ PLIANCE OUTLET.

They will turn on automatically

with

the radio.

To turn on the appliance automatically

some pre¬

determined

time, follow the AUTOMATIC

CLOCK-RADIO

OPERATION

instructions.

The radio will also come on

with the appliance, serving as a reminder that the appliance

has been turned on. If radio reception is not desired to¬

gether with appliance operation,

just turn VOLUME knob to

minimum.

Appliances

may also be operated manually, by following

MANUAL RADIO OPERATION instructions.

radio recep¬

tion is not desired with appliance operation, just turn VOL¬

UME knob to minimum.

If radio is to be used alone, be sure to remove appliance

plug from APPLIANCE

OUTLET.

SERVICE NOTES

TO REMOVE RADIO CHASSIS FROM CABINET

1. Remove the four screws which hold the rear cover; dis¬ connect the antenna and appliance outlet leads and remove

the cover.

2. Pull off the two control knobs from the front of the cabi¬ net.

3. Remove the Phillips head screw under the tuning knob on the front of the receiver.

4. Disconnect

the chassis power leads from clock.

Disconnect

speaker leads from chassis.

6. From the back, remove the three screws that mount the chassis to the cabinet,

7. Remove the chassis from the cabinet.

TO REMOVE CLOCK FROM CABINET

1. Remove the two speaker mounting screws and remove speaker.

2. Pull off the operation selector knobs on front of cabinet.

3. Remove the four screws that hold the clock bracket to

the cabinet.

4. Carefully remove the clock and clock bracket from the cabinet.

Unsolder

leads and remove the two small nuts and

washers mounting the clock to the clock bracket.

CLOCK REPAIR INFORMATION

Duplex timers can be repaired at Duplex Clock Co. , Inc.

29 Cherry Avenue, Waterbury,

Connecticut.

The timer should be removed from the radio cabinet and packed carefully in order that no further damage results in shipment.

An acknowledgement

with a quotation and a request for payment will be sent to the dealer before the repair is made. The timer will be returned to the dealer on receipt of pay¬ ment. If the timer is within warranty, repairs will be made on a no-charge basis.

USE OF ISOLATION TRANSFORMER

The chassis of this receiver is connected directly to the power line, however, the power cord circuit is broken by an interlock when the cabinet rear cover is removed. When servicing

aligning this chassis from AC, an isolation

transformer

should be inserted between the power line and

the chassis.

CIRCUIT DESCRIPTION

1. The circuit of this chassis is conventional

there are

no built-in resistors

capacitors.

Leads are plated on both sides of the chassis base, thereby replacing the usual connecting wires and making wiring more uniform.

2. The metal plating extends through all the holes on the chassis, connecting

circuits on the front with those on the

rear.

3. Reference

the schematic diagram and to chassis will

permit the circuit to be traced easily.

SAFETY PRECAUTIONS

1. Do not service the chassis on a metal plate, because of

the possibility

of a

short circuit.

2. Use caution when handling the chassis with power ap¬ plied, because all high voltage leads are exposed.

3. The outer edges of the chassis and various plated areas are at ground potential.

COMPONENT

REPLACEMENT

1. To prevent tube breakage,

remove them before replac¬

ing components.

2. WHEN REMOVING

DEFECTIVE

COMPONENTS

USE ONLY A SMALL SOLDERING IRON (60 WATTS OR LESS) TO AVOID DAMAGE TO THE WIRING. DO NOT USE A SOLDERING

GUN. WARNING: THE LEADS ARE VERY

THIN, AND EXCESSIVE

HEAT WILL BURN THEM OR

LOOSEN THEM FROM THE BASE MATERIAL.

3. Plated connections

leads, if damaged, may be re¬

placed with a jumper of regular hookup wire.

4. It is recommended

that multiple lug components

re¬

moved by immersing

all the lugs simultaneously

into a con¬

trolled temperature

soldering

pot. Motorola Part Number

66T632703.

The component may then be lifted off the chas¬

sis easily. If a soldering pot is not available, heat each lug

individually

with a small soldering iron and shake or brush

off as muchmolten

solder as possible. Then, by alternately

heating and loosening each lug, the entire component will be freed.

5. An individual tube clip may be removed by squeezing it

it with pliers and then unsoldering

it. The new clip snaps

into the hole.

6. Resistors

capacitors

may be removed by unsoldering

one end at a time.

CAUTION: Clean all the solder from the holes before in¬ stalling a new component.

not let the solder run onto an

adjacent lead, as a short circuit will be created.

Page 3

ALIGNMENT

Use an isolation transformer

between the power line and

the receiver.

not available, connect low side of genera¬ tor to ground (outer chassis edges) through a . 1 mf capaci¬ tor.

Connect a low range output meter across speaker voice

coil and set volume control to maximum.

Set signal generator output to produce .40 volts across voice coil. As stages are aligned, reduce generator output, to maintain the .40 volt level to avoid overloading

receiver.

STEP

DUMMY

ANTENNA

GENERATOR CONNECTION

GENERATOR

FREQUENCY

(400 cycle mod)

GANG

SETTING

ADJUST

REMARKS

IF ALIGNMENT 1

. 1 mf

RF ALIGNMENT

. 1 mf

Grid of conVo (pin 7, 12BE6)

Grid of conv0 (pin 7, 12BE6)

Radiation loop*

455 Kc

1620 Kc

1400 Kc

Fully open

Tune for max

1, 2, 3 & 4

(IF cores)

5 (Osc)

6 (Ant)

Adjust for maximum.

Use

insulated screwdriver.

Adjust for maximum.

^Connect generator output across 5" diameter,.

turn loop and couple inductively to receiver loop. Keep loops at least

12" apart.

ALIGNMENT DATA

Front

1620 Kc

1400 Kc

12BA6 R8

Power

Interlock

]—

■

gsa \

50C5

»e

■

• _ . . ___

Page 4

NOTE: When ordering parts, specify model number of set in addition to part number and description of part.

Ref.

Part

No.

Number

ELECTRICAL PARTS

Capacitors

Description

List

Price

Part Number

MECHANICAL PARTS

Description

C-l C-2 C-3 C-4 C-5

19K630263 8A120842 21R120853 23B630155 8K490232

Variable,

2-gang............

2.85 Paper, tubular: Ceramic Disc; Electrolytic

Molded, paper;

.05 mf 200V

.01 ml 450V.,

50-30 mf/150V

.047 mf 400V

.40 .25

1.90 .30

42B610632

Clip, tube pin.per/c

29A630230

Lug, terminal;

connector...doz

28A631078

Plug, line cord (interlock)...,...

29A631120

Terminal,

pin (on spkr & ant leads)

.....

,doz

CABINET PARTS

CR-1 21B630180

E-l

72D632676

L-l

*1V632714

L-2

24B630327

LS-1

50C630287

or 50C631455

Resistors

Note:

Multiple Capacitor

Resistor

Plate......................

Clock Assembly;

Duplex NOTE: SEE SERVICE NOTES FOR CLOCK REPAIR INFORMATION

Antenna Loop & Back Cover

Assembly:

incl AC recept &

line cord...............

■

Coil, oscillator.........

.85

3.70** .85

Speaker, PM; 4"; 3.2 ohm

VC; incl T-3..

4.70**

exch 3.55

All resistors

are insulated

carbon

type unless otherwise

specified

*16K632657

♦

6K632659

*16X632660

*16K632661

30B630227

61A622114

♦

36K632662

*36X632663

*36X632667 *36X632668 *36X632665 *36X632666

1V630275

*34X632664

mahogany (55C1) white (55C2)... mint green

Cabinet,

plastic:

Cabinet,

plastic:

Cabinet,

plastic:

(55C3)....

Cabinet,

plastic:

clover pink

(55C4)....

Cord, line:

with plug

recept ...

Crystal,

plastic.........

Knob, operation

selector:

(55C1,3,4).....................

Knob, operation

selector:

white

(55C2) .

gray (55C1,3,4),.

. .

white (55C2).......

gray (55C1,3,4)....

white (55C2).......

with lugs.

interlock

gray

a O • • «

Knob, tuning: Knob, tuning: Knob, volume: Knob, volume: Receptacle,

appliance:

R-l

6K119405

22,000 20% 1/2W..

« « « •

.doz

1.20

3S115138

R-2

6K119407

3.3 meg 20% 1/2W.

• 0*0

.doz 1.20

R-3

6K119402

100 20% 1/2W.

P • O •

.doz 1.20

R-4

6K119407

3.3 meg 20% 1/2W.

o • o o

.doz 1.20

3S121050

R—5 18A630279

Volume Control:

meg.

« « o «

.95

R-6

6K119403

150 20% 1/2W ...

, .

O 0 0 0

,doz

1.20

R-7

6K121276

1000 20% 2W......

• OOP

.25

3S115237

R-8

6B119401

27 10% 1/2W......

o o o •

.doz

1.20

15A630871

T—1

♦

4K632782 Trans, 1st IF: 455

Kc.

1.40

31A630229

T-2

24K632039 Trans, 2nd IF: 455

Kc.

1.30

T-3

25B630280

Trans, output......

• • • •

1.00

29A620057

PRICES SUBJECT TO CHANGE WITHOUT

♦

New Item , Appears in any List for !

Scale, clock dial.,..,..,......,..

Screw, machine:

6-32 x 1-9/16

Phillips

flat head (chassis

mtg -

through front of cabinet)....»doz

Screw, thread-cutting:

#% x

1/2

plain hex head (chassis

spkr

mtg)..........................doz

Screw, thread-cutting:

#6 x

5/16

plain hex head (clock mtg)....doz

Shell, appliance

recept mtg..,.,,.

Terminal Strip (AC connector

clock mtg brkt)..................

Terminal,

pin (on ant loop leads)

..............................doz

**Plus Federal Excise Tax at Current Rate

***Prices Furnished

Upon Request

List

Price

.50

.35

.10

.20

***

1.35 .15

.15

.15 ,25

.25 .15 .20 .35 .60

.20

,25

.40 .05

.25

Motorola 55C1, 55C2, 55C3, 55C4 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual