Sony MDS-PC2 service manual Table of Contents, Disassembly, Diagrams, Exploded Views

SAFETY 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, “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). 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 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 pas- sive 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

0.15μF		AC
	1.5kΩ	voltmeter
		(0.75V)

Earth Ground

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

TABLE OF CONTENTS
1. SERVICING NOTE	6
2. GENERAL	12
3. DISASSEMBLY
3-1. Case and Front Panel	14
3-2. MD Mechanism	14
3-3. Slider (CAM)	15
3-4. Base Unit (MBU-5A) BD Board	15
3-5. SW Board and Loading Motor (M103)	16
4. TEST MODE	17
5. ELECTRICAL ADJUSTMENTS	22
6. DIAGRAMS
6-1. Circuit Boards Location	31
6-2. Block Diagrams
• BD Section	33
• Main Section	34
6-3. Printed Wiring Board – BD Section –	36
6-4. Schematic Diagram – BD (1/2) Section –	37
6-5. Schematic Diagram – BD (2/2) Section –	38
6-6. Schematic Diagram – Main (1/2) Section –	39
6-7. Schematic Diagram – Main (2/2) Section –	40
6-8. Printed Wiring Board – Main Section –	41
6-9. Schematic Diagram – Panel Section –	42
6-10. Printed Wiring Board – Panel Section –	43
6-11. Schematic Diagram – Power Section –	44
6-12. Printed Wiring Board – Power Section –	45
6-13. Schematic Diagram – BD Switch Section –	46
6-14. Printed Wiring Board – BD Switch Section –	46
6-15. IC Block Diagrams	46
6-15. IC Pin Functions	49
7. EXPLODED VIEWS
7-1. Cabinet Section	53
7-2. Mechanism Section (MDM-5A)	54
7-3. Base Unit Section (MBU-5A)	55
8. ELECTRICAL PARTS LIST	56

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