Sony MDS-JD320 service manual Table of Contents, Disassembly, Diagrams, Exploded Views

SAFETY CHECK-OUT

After correcting the original service problem, perform the following safety checks 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

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” 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 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
0.15 ∝F		Ω	Voltmeter
	1.5 k		(0.75 V)

Earth Ground

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

MODEL IDENTIFICATION

— BACK PANEL —

Parts No.

TABLE OF CONTENTS
1. SERVICING NOTE	5
2. GENERAL	8
3. DISASSEMBLY
3-1. Case and Front Panel Assembly	9
3-2. Bracket (T), (L) and (R)	9
3-3. BD Board	10
3-4. SUB Chassis	10
3-5. Shutter Assembly	11
3-6. Over Write Head	11
3-7. Slider Complete Assembly	12
4. TEST MODE	13
5. ELECTRICAL ADJUSTMENTS	16
6. DIAGRAMS
6-1. Brock Diagrams
• BD Section	21
• Main Section	23
6-2. Circuit Boards Location	25
6-3. Printed Wiring Board — BD Section —	27
6-4. Schematic Diagram — BD Section (1/2) —	29
6-5. Schematic Diagram — BD Section (2/2) —	31
6-6. Printed Wiring Board — Main Section —	33
6-7. Schematic Diagram — Main Section (1/3) —	35
6-8. Schematic Diagram — Main Section (2/3) —	37
6-9. Schematic Diagram — Main Section (3/3) —	39
6-10. Printed Wiring Board — Display Section —	41
6-11. Schematic Diagram — Display Section —	43
6-12. Printed Wiring Board — Switch Section —	45
6-13. Schematic Diagram — Switch Section —	47
6-14. IC Brock Diagrams — BD Section—	49
6-15. IC Pin Functions	54
7. EXPLODED VIEWS
7-1. Main Section	63
7-2. Front Panel Section	64
7-3. Mechanism Deck Section (1) (MDM-3GC)	65
7-4. Mechanism Deck Section (2) (MDM-3GC)	66
8. ELECTRICAL PARTS LIST	67

Parts No.	Model
4-990-651-1	US model
4-990-651-4	Canadian model
4-990-651-5	AEP model

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