Sony tc r303 Service Manual

SERVICE MANUAL

Dolby noise reduction manufactured under license from
Dolby Laboratories Licensing Corporation.

00

“DOLBY” and the double-D symbol

Dolby Laboratories Licensing Corporation.

are trademarks of

SPECIFICATIONS

Canadian Model

Model Name Using Similar

Tape Transport Mechanism Type

t---

US Model

AEP Model

Recording system

Fast-forward and rewind time

Bias frequency
Signal-to-noise ratio (NAB, at peak level)

Total harmonic distortion

Frequency response

Wow and flutter
inputs Microphone inputs (phone jacks)

outputs

4-track 2-channel stereo

Approx. 90 sec. (with C-60 cassette)
105 kHz

B
ON ON

65dB

TYPE II (Sony UX

1.0% (with Sony METAL-ES cassettes)

DOLBY NR OFF

l With TYPE

30

15,000 Hz (±3

30

13,000 Hz (±3 dB, 0 VU recording)

l With TYPE II cassette (Sony UX-S)

30 15,000 Hz

l With TYPE

20

14,000 Hz

0.07% WRMS (NAB)

Sensitivity 0.25
For a low-impedance microphone

Line inputs (phono jacks)

Sensitivity 77.5
Input impedance 47 kilohms

Line outputs (phono jacks)

Output level 0.44 V
impedance 47 kilohms
Load impedance over 10 kilohms

Headphones output (stereo phone jack)

Output level -28
8 ohms

S)

IV

cassette (Sony METAL-ES)

dB)

(±3 dB)

I

cassette (Sony

(±3 dB)

mV

(-70

mV

(-20

dB

64
61 dB

HF-S)

dB)

dB)

(-5 dB)

at load

at load impedance

TYPE

dB

67dB

C-TYPE

71 dB
70dB

General

Power requirements

Power consumption

Dimensions

Weight

SAFETY-RELATED COMPONENT WARNING!!

COMPONENTS IDENTIFIED BY SHADING AND MARK

A

ON THE SCHEMATIC DIAGRAMS AND IN THE

PARTS LIST ARE CRITICAL TO SAFE OPERATION.
REPLACE THESE COMPONENTS WITH SONY PARTS
WHOSE PART NUMBERS APPEAR AS SHOWN IN THIS
MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.

ATTENTION AU COMPOSANT AYANT RAPPORT

LES COMPOSANTS
UNE MARQUE
MATIQUES
POUR LA

PLACER CES COMPOSANTS DUE PAR DES
SONY DONT LES
MANUEL OU DANS LES SUPPLEMENTS
SONY.

USA and Canadian
UK model: 240V ac,

AEP model: 22OV ac, 50/60 Hz

20 Watts
Approx. 430

(17 x 4% x 10% inches)
including projecting parts and controls
Approx. 3.9 kg (8 Ibs 10 oz)

A LA

ET LA

SECURITE

h

LISTE

DE FONCTIONNEMENT. NE

NUMEROS

x

SECURITE

IDENTIFIES

SUR LES

DES

model: 120

110 x 255 mm (w/h/d)

PAR UNE TRAME ET

DIAGRAMMES SCHE-

PIECES

SONT CRITIQUES

SONT

DONNES

50/60Hz

PUBLIES

Vac,

60 Hz

REM-

PIECES

DANS CE

PAR

STEREO CASSETTE DECK

SONY

TC-R303

TABLE OF CONTENTS

Title

Section 1
Section 1.

Section 2.
Section 3.

Section 4.
Section 5.
Trouble Checks,

Description

Specifications.
Model Identification
Location and Function of Controls.
Block Diagram
Adjustments.
Diagrams

3-l.

Mounting Diagram.
Schematic Diagram

3-2.

Exploded Views and Parts List.
Electrical Parts List

Page

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US, Canadian Model: AC: 120 V

AEP Model: AC: 220 V ~

!

UK Model: AC: 240 V

1

.

2
3
5

.ll

12

.15

19

.24

60 Hz 20 W

50/60

~ 50/60

Hz 20 W
Hz 20 W

,

,

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SAFETY CHECK-OUT (US Model)

After correcting the original service problem,
perform the following safety check before releasing
the set to the customer:
Check the antenna terminals, metal trim, “metallized”
knobs, screws, and all other exposed metal parts for

AC leakage. Check leakage as described below.

LEAKAGE TEST

The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5

current can be measured by any one of three
methods.

1.

A commercial leakage tester, such as the

Simpson
manufacturers’ instructions to use these instru­ments.

2.

A battery-operated AC
Precision
this job.

mA (500

229

or RCA WT-540A. Follow the

245

digital multimeter is suitable for

microampres).

milliammeter.

The Data

Leakage

3.

Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC

meter.
analog meters must have an accurate low­voltage scale. The Simpson 250 and Sanwa

SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a
suitable. (See Fig. A)

1

Fig.

A. Using an AC voltmeter to check AC leakage.

The “limit”

0.15µF

indication is

To Exposed Metal

Parts

on

set

Earth Ground

4

2V

AC range are

AC

voltmeter
(0.75 V)

0.75V,

volt-

so

LOCATION AND FUNCTION OF CONTROLS
FRONT PANEL’

TAPE COUNTER and RESET button
The tape counter
recording and playback To reset to zero, press the RESET
button

Cassette holder

provides convenient

reference points for

TC-R303 T

HEADPHONES jack (stereo phone jack)

Tape operation buttons

M

(leftward fast winding) button

4

(reverse) button

)

(forward) button

DW

(rIghtward fast winding) button

l

REC (record) button

n

(stop) button

II PAUSE button

Press

to stop the tape momentarily during recording or
playback To disengage the pause mode, press
again

0

REC MUTE (record muting) button

it

REAR PANEL

J

3

2-1. MECHANICAL ADJUSTMENTS

SECTION 2

ADJUSTMENTS

2-2. ELECTRICAL ADJUSTMENTS

PRECAUTION

Clean the following parts with a

1.
alcohol-moistened swab:

record/playback head
erase head
capstan

Demagnetize the record/playback head with a

2.

pinch roller
rubber belts

idler

head demagnetizer.

Do not use a magnetized screwdriver for the

3.

adjustments.
After the adjustments, apply suitable locking

4.

compound to the parts adjusted.
The adjustments should be performed with the

5.

rated power supply voltage unless otherwise
noted.

Torque Measurement

Torque

Torque meter

FWD
FWD

Back tension
REV
REV

Back tension
FF, REW

CQ-102C

CQ-102C

CQ-102RC

CQ-102RC

CQ-2OlB

Meter reading

30 to 70

(0.43 to 0.97 oz-inch)

2 to 6 g-cm

(0.03 to 0.08 oz-inch)

30 to 70 g-cm

(0.43 to 0.97 oz-inch)

2 to 6 g-cm

(0.03 to 0.08 oz-inch)

90 to 160 g-cm

(1.3 to 2.2 oz-inch)

denatured-

g-cm

The adjustment should be performed in the

Note:

order given in this service manual.
The adjustments should be performed for both

L-CH and R-CH.

0 Switches and controls should be set as follows

unless otherwise specified.

DOLBY NR switch:
TIMER switch:

l Standard Record:

OFF
OFF

Deliver the standard input signal level to the input

jack and set the REC LEVEL control to obtain the

standard output signal level.

-

Record Mode

af osc

-

600

s2

LINE IN

VTVM

/

LINE OUT

Standard Input Level

L

Standard Output Level

Ji

Tape Speed Adjustment

Record/Playback

Head Azimuth Adjustment

Procedure:

Mode: FWD playback

speed checker

L FM-30
digital frequency

test tape

Ws-488
(3 k Hz,0 dB)

c

LINE OUT

counter

m

0

I

?Jl

Specification:

1

Speed checker

r~

-1-+1%

1

Digital frequency counter

2,970-3,030Hz

I

Frequency difference between the beginning
and the end of the tape should be within 0.84%
(25Hz).

Adjustment Location:

Adjust by using a screwdriver. Turning in the

direction of clockwise, speed will be fast.

Procedure: Adjust both NOR and REV.

Mode: playback

1.

test tape
P-4-A 100

2. Turn

the adjustment screw for the maximum

VTVM

output levels. If these levels do not match, turn
the adjustment screw until both of output

levels match together within 1

dB.

1

I

L-CH

peak

\

position

/

peak

peak

Adjustment resistor

motor

3. Phase Check
Mode: playback

Test

tape

P-4-A100

(10kHz, -1OdB)

A

L-CH

Adjustment Location:

-

Record/Playback head

oscilloscope

LINE

OUT

-

-8-

FWD

Adjustment screw

REV