Sony 4-216-840-0 service manual Section Servicing Notes, Table of Contents, Diagrams

	TABLE OF CONTENTS
SELF-DIAGNOSIS FUNCTION		2
1.	SERVICING NOTES	4
2.	GENERAL	11
3.	DISASSEMBLY	12
4.	TEST MODE	16
5.	ELECTRICAL ADJUSTMENTS	21

6.DIAGRAMS

6-1.	IC Pin Function Description	30
6-2.	Block Diagram – SERVO Section –	37
6-3.	Block Diagram – MAIN Section –	39
6-4.	Note for Printed Wiring Boards and
	Schematic Diagrams	42
6-5.	Printed Wiring Board – BD Board –	43
6-6.	Schematic Diagram – BD Board (1/2) –	45
6-7.	Schematic Diagram – BD Board (2/2) –	47
6-8.	Schematic Diagram – SW Board –	49
6-9.	Printed Wiring Board – SW Board –	49
6-10. Printed Wiring Boards – TRANS Board –		53
6-11. Printed Wiring Board – MAIN Board –		55
6-12.	Schematic Diagram – MAIN Board (1/2) –	57
6-13. Schematic Diagram
	– MAIN Board (2/2), TRANS Board –	59
6-14. Printed Wiring Boards – PANEL/PANEL 2 Boards – ...		61
6-15.	Schematic Diagram – PANEL/PANEL 2 Boards –	63
7.	EXPLODED VIEWS	66
8.	ELECTRICAL PARTS LIST	70

SECTION 1

SERVICING NOTES

SAFETY CHECK-OUT

After correcting the original service problem, perform the follow- ing 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.

1.A commercial leakage tester, such as the Simpson 229 or RCA WT-540A. Follow the manufacturers’ 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 “limit” indica- tion is 0.75 V, so analog meters must have an accurate low- voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex- amples of a passive VOM that is suitable. Nearly all battery operated digital multimeters that have a 2 V AC range are suit- able. (See Fig. A)

To Exposed Metal

Parts on Set

0.15 ∝F	1.5 k Ω	AC
		voltmeter
		(0.75 V)

Earth Ground

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

MODEL IDENTIFICATION

— BACK PANEL —

Part No.

MODEL	Part No.
US model	4-216-840-0¹
Canadian model	4-216-840-1¹
Singapore model	4-216-840-2¹
AEP model	4-216-840-3¹
UK model	4-216-840-4¹

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