Sony ta av 621 service manual

Page 2

TA- AV521/AV621

TABLE OF CONTENTS SAFETY CH ECK-OUT

Section Title After correcting the original service problem,

perform the following safety check before releasing

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m
m

- GENERAL ' ' 3 the set to the customer:
Check the antenna terminals, metal trim, metallized
knobs, screws, and all other exposed metal parts for
2' DIAGRAMS AC leakage. Check leakage as described below.
271, IC Description ............................... 7
2-2. Circuit Boards Location ~ - - 11 LEAKAGE TEST
2-3. Printed Wiring Boards-- - 12

The AC leakage from any exposed metal part to

2-4. Schematic Diagram -Main Section- -- . 17
. earth ground and from all exposed metal parts to any
2-5" Schematic Diagram -Power Section- """ 21 exposed metal part having a return to chassis, must
2-6. Semiconductor Lead Layouts --------------- 23 not exceed 0.5 mA (500 microampers). Leakage
2-7.IC Block Diagrams --------------------------- 24 current can be measured by any one of three
methods.

3. EXPLODED VIEWS l. A commercial leakage tester, such as the
3-1, FRONT PANEL SECTION ................... 25 Simpson 229 or RCA WT-S40A. Follow the
3_2~ BACK PANEL SECTION .................... 26 manufacturers instructions to use these instru-

ments.

4- ELECTRICAL PARTS LIST .............. _ 27 2. A battery-operated AC milliammeter. The Data

Precision 245 digital multimeter is snitable for
this job.

3. Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The limit indication is 0.75V, so
analog meters must have an accurate low-

MODEL IDENTICATION VOltage scales The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital

SONY TA-AVSZl multimeters that have a 2V AC range are
' MODEL NO. TA-AV521 suitable. (See Fig.A)

INTEGRATED STEREO AV AMPLIFIER

- Specification Label -

WWII/[m 5......de

Pam on Set

SERlAL N0
MADE IN JAPAN
AC
0.15uF §I.5kn / voltmeter
AC 120V ~ 60H: 250W (0.75 V}

SAFETY-RELATED COMPONENT WARNINGI!

COMPONENTS IDENTIFIED av MARK A on DOTTED '1- Earth 60
LINE WITH MARK A oN THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE

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

OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUBv
LISHED BY SONY.