Page 2
Ñ 3 Ñ TABLE OF CONTENTS
1. SERVICING NOTE
.......................................................... 4
2. GENERAL .......................................................................... 5
3. DISASSEMBLY
3-1. Front Panel .......................................................................... 26
3-2. Balance Board, Display Board and Volume Board ............. 26
4. TEST MODE ..................................................................... 27
5. ELECTRICAL ADJUSTMENTS ............................... 28
6. DIAGRAMS
6-1. IC Pin Functions ................................................................. 30
6-2. Circuit Boards Location ...................................................... 47
6-3. Block Diagrams
¥ Input/Output Section ........................................................ 49
¥ Power Amp Section ......................................................... 51
¥ DA Section ....................................................................... 53
¥ DSP Section ..................................................................... 55
¥ AC-3 (RF) Section ........................................................... 57
¥ OSD Section .................................................................... 59
¥ OSD Control Section ....................................................... 61
¥ Panel Section ................................................................... 63
¥ Power Section .................................................................. 65
6-4. Printed Wiring Board Ñ Input/Output Section Ñ ............. 68
6-5. Schematic Diagram Ñ Input/Output Section Ñ ................ 71
6-6. Schematic Diagram Ñ Power Amp Section Ñ .................. 75
6-7. Printed Wiring Board Ñ Power Amp Section Ñ ............... 79
6-8. Printed Wiring Board Ñ Digital Section Ñ ....................... 83
6-9. Schematic Diagram Ñ Digital (D/A) Section Ñ ............... 87
6-10. Schematic Diagram Ñ Digital (Control) Section Ñ ....... 91
6-11. Schematic Diagram
Ñ Digital (Dolby AC-3) Section Ñ ................................. 95
6-12. Printed Wiring Board Ñ Panel Section Ñ ....................... 98
6-13. Schematic Diagram Ñ Panel Section Ñ ....................... 101
6-14. Schematic Diagram Ñ OSD Section Ñ ........................ 105
6-15. Printed Wiring Board Ñ OSD Section Ñ ...................... 109
6-16. IC Block Diagrams ......................................................... 112
7. EXPLODED VIEWS
7-1. Case Section ...................................................................... 117
7-2. Front panel Section ........................................................... 118
7-3. OSD Board Section ........................................................... 119
7-4. Chassis Section ................................................................. 120
8. ELECTRICAL PARTS LIST ...................................... 121SAFETY 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). Leak-
age 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)
Notes on chip component replacement
¥ Never reuse a disconnected chip component.
¥ Notice that the minus side of a tantalum capacitor may be
damaged by heat.
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.
Fig. A. Using an AC voltmeter to check AC leakage.
MODEL IDENTIFICATION
Ñ BACK PANEL Ñ
Parts No.Model
4-989-885-4
4-989-885-5
US model
Canadian model
Parts No.
AC
voltmeter
(0.75V) 1.5k W 0.15 mF
Earth Ground To Exposed Metal
Parts on Set
