Sony tc rx 77 service manual

Page 1

TC-RX77/RX77ES

SERVICE

MANUAL

Dolby noise redUction manufactured Under license from
Dolby Laboratories Licensing Corporation.
"DOLBY and the double-D symbol DI] are trademarks of
Dolby Laboratories Licensing Corporation

US Model
Canadian Model

TC- RX77ES

AEP Model

TC-RX77

Recording system
Fast-winding time

Bias
Heads

Motors

4-track 2-channel stereo

SPECIFICATIONS

Approx. 90 sec. (with Sony (3-60

cassette)
AC bias

Erasing head x 1 (territe head)
Playback/Recording head x 1 (LA

head)

Capstan motor x 1 (DC sen/o motor)

Reel motor x 1 (DC motor)

Mode! Name Using Similar Mechanism TC-RXTO/RXTOES

TCM - 200R6

Tape Transport Mechanism Tyne

lnputs
Line inputs Sensitivity 775 mV
(phone jacks) lnput impedance 47 k ohms
Microphone inputs Sensitivity (For a 025 mV
(phone jacks) low-impedance
microphone)
Outputs

$39:er (tmlechanical drive) motor X 1 Line outputs Rated output level 032 V at a load
. . . o o I (phono jacks) impedance of 47
Signal-to-notse ratio (at peak level) k ohms
Dolby NR switch B-Type C-Type ~
Cassette OFF ON ON Load impedance Over 10 k ohms
Head hones Out ut level 0-125 mW ata
Type lV (Sony METAL»SLT) 59 dB 67 dB 74 dB (sere; phone p load impedance of
Type ll (Sony UX-S) 58 dB 66 dB 73 dB jack) 32 ohms
Type I (Sony HF-S) 56 dB 64 dB 71 GE
General

Total harmonic distortion

1% (with Sony METAL-8LT cassette)

Frequency response (DOLBY NR OFF)

Type IV cassette
(Sony METAL-8LT)

20- 20.000Hz (i 3db,IEC)
(US, Canadian models)

25~19,000H2 (i 3db,|EC) (AEP)

Type II cassette
(Sony UX-S)

25 - 17,000 Hz (:3 dB, lEC)

Type | cassette
(Sony HF-S)

25 - 16,000 Hz (:3 dB, IEC)

Wow and flutter

«20.09% w. Peak (IEC)
006% WRMS (NAB)
:0.1e% w. Peak (DIN)

Power requirements
RX77ES : 120 V AC. 60H: (US. Canadian models)

RX77 : 220V AC, 50/60Hz (AEP model)
Power consumption 20 W
Dimensions Approx. 430 x 123 x 300 mm (w/h/d)
(17 x 47/3 >< 117/3 inches)
including projecting parts and controls
Weight Approx. 4.7 kg (10 lbs 6 oz)

Supplied accessory
Audio connecting cords (2)

Design and specifications subject to change without notice,

STEREO BASSE E DECK
ONYFD

Page 2

TC- RX77 X77ES

TABLE OF CONTENTS

Section Title Page
Specification ................ . ......................... 1
Model Identification ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2
Safety Check-Out ............................. .. ..... 2
1. GENERAL ....... 3
2. D|SASSEMBLY .................. . .................. 4
3ADJUSTMENTS .................. . . ................ 7

8- 1. Mechanical Adjustment ..................... 7

3-2. Electrical Adjustment ~~~~~ . ~~~~~~~~~~~~~~~~~~ 7

4. DIAGRAMS
4- 1. Semiconductor Lead Layout~

4-2. Circuit Boards Location ~~~~~

4-3. Printed Wiring Boards .. --------- - 12
4-4. Schematic Diagram ~~~~~~~~~~~~~~~~~~~~~~~ 17
5. EXPLODED VIEWS .................. .. ........... 19
5-1. Front Panel Section ~~~~~~~~~~~~~~~~~~~~~~~ 23
5-2. Chassis Section ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 24

-25
~26

5-3. Mechanism Section (TCMZOORS)
5-4. Mechanism Section (TCM-ZOORB)

6. ELECTRICAL PARTS LIST ~~~~~~~~~~~~~~~~~~~~~ 27

SAFETY-RELATED COMPONENT WARNINGII

COMPONENTS IDENTIFIED BV MARK A OR DOTTED
LINE WITH MARK A ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL T0 SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.

ATTENTION AU COMPOSANT AYANT RAPPORT
A LA sscumrés

LES COMPOSANTS IDENTIEIés PAR UNE MARQUE A
sun LES DIAGRAMMES scHEMATIouss ET LA LISTE
DES PIECES SONT camouEs eoua LA sécumrE
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR oss PIECES SONY DONT LES
NUMéRos SONT DONNés DANS cE MANUEL ou
DANS LES SUPPLEMENTS PUBLIES PAR SONY.

SAFETY CH ECK-OUT

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 mA (500 microampers). Leakage
current can be measured by any one of three
methods.

I. A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers instructions to use these instru-
ments.

2. A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.

3. Measuring the voltage drop across a resistor by
means of a VOM or batteryvoperated AC volt-
meter. The limit indication is 0.75V, so
analog meters must have an accurate low-
voltage 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 2V AC range are
suitable. (See Fig. A)

To Exposed Metal
Parts on Set

/AC

0.15MF $1.5: voltmeter
I0. 75 V)

7' Earth Ground

Fig. A. Using an AC voltmeter to check AC leakage.