Page 1
Ñ 2 Ñ TABLE OF CONTENTS
1. GENERAL....................................................................
3
2. DIAGRAMS
2-1. Circuit Boards Location ..................................................... 4
2-2. Printed Wiring Board Ñ Main Section Ñ ......................... 5
2-3. Schematic Diagram Ñ Main Section Ñ ............................ 7
2-4. Printed Wiring Board Ñ Panel Section Ñ ....................... 10
2-5. Schematic Diagram Ñ Panel Section Ñ .......................... 13
2-6. IC Pin Function
¥ IC101 System Control (M37471M2-458SP) ................. 16
3. EXPLODED VIEWS
3-1. Front Panel Section .......................................................... 17
3-2. Chassis Section ................................................................. 18
4. ELECTRICAL PARTS LIST.................................... 19SAFETY CHECK-OUT
After correcting the original service problem, perform the follow-
ing safety checks before releasing the set to the customer:
Check the antenna terminals, metal trim, ÒmetallizedÓ knobs, screws,
and all other exposed metal parts for AC leakage. Check leakage as
described below.
LEAKAGE
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.
1. A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturersÕ instructions to use these
instruments.
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 battery-operated AC voltmeter. The ÒlimitÓ indication is 0.75
V, so analog meters must have an accurate low-voltage scale.
The Simpson 250 and Sanwa SH-63Trd are examples of a pas-
sive VOM that is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are suitable. (See Fig. A)
ATTENTION AU COMPOSANT AYANT RAPPORT
Ë LA SƒCURITƒ!!
LES COMPOSANTS IDENTIFIƒS PAR UNE MARQUE ! SUR
LES DIAGRAMMES SCHƒMATIQUES ET LA LISTE DES
PIéCES SONT CRITIQUES POUR LA SƒCURITƒ DE
FONCTIONNEMENT. NE REMPLACER CES COMPOSANTS
QUE PAR DES PIéCES SONY DONT LES NUMƒROS
SONT DONNƒS DANS CE MANUEL OU DANS LES
SUPPLƒMENTS PUBLIƒS PAR SONY. SAFETY-RELATED COMPONENT WARNING !!
COMPONENTS IDENTIFIED BY MARK ! OR DOTTED LINE
WITH MARK ! 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.
MODEL IDENTIFICATION
Ñ BACK PANEL Ñ
PARTS No.
PARTS No.
US,Canadian model
Hong Kong model
Singapore model
Tourist model4-977-717-3¹
4-977-717-0¹
4-977-717-1¹
4-977-717-2¹
Fig. A. Using an AC voltmeter to check AC leakage.
To Exposed Metal
Parts on Set
0.15µF1.5kAC
voltmeter
(0.75V)
Earth Ground
