MHC-VX3 (serv.man2) - Sony Audio Service Manual (repair manual). Page 3

3

1.

Check the area of your repair for unsoldered or poorly-soldered
connections.  Check the entire board surface for solder splashes
and bridges.

2.

Check the interboard wiring to ensure that no wires are
"pinched" or contact high-wattage resistors.

3.

Look for unauthorized replacement parts, particularly
transistors, that were installed during a previous repair.  Point
them out to the customer and recommend their replacement.

4.

Look for parts which, through functioning, show obvious signs
of deterioration.  Point them out to the customer and
recommend their replacement.

5.

Check the B+ voltage to see it is at the values specified.

6.

Flexible Circuit Board Repairing

• Keep the temperature of the soldering iron around 270˚C

during repairing.

• Do not touch the soldering iron on the same conductor of the

circuit board (within 3 times).

• Be careful not to apply force on the conductor when soldering

or unsoldering.

After correcting the original service problem, perform the

following safety checks before releasing the set to the

customer.

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3-1.

Case ···················································································· 7

3-2.

Front Panel Section ···························································· 7

3-3.

Tape Mechanism Deck Section
(TCM-230AWR2/230PWR2) ············································ 8

3-4.

CD Mechanism Deck section (CDM38L-5BD34L) ·········· 8

3-5.

Main Board ········································································· 9

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7-1.

Circrit Boards Location ···················································· 18

7-2.

Block Diagrams ································································ 19

•

 CD Section ····································································· 19

•

 Video Section ································································· 20

•

 Tape Deck Section ························································· 21

•

 Main Section ·································································· 22

•

 Display/Key Con Section ·············································· 23

7-3.

Printed Wiring Board   Main Section ······························· 25

7-4.

Schematic Diagram   Main Section (1/4) ························· 26

7-5.

Schematic Diagram   Main Section (2/4) ························· 27

7-6.

Schematic Diagram   Main Section (3/4) ························· 28

7-7.

Schematic Diagram   Main Section (4/4) ························· 29

7-8.

Printed Wiring Board   CD Section ·································· 30

7-9.

Schematic Diagram   CD Section ····································· 31

7-10. Printed Wiring Board   CD Motor Section ······················· 32
7-11. Schematic Diagram   CD Motor Section ·························· 33
7-12. Printed Wirint Board   Tape Deck Section ······················· 34
7-13. Schematic Diagram   Tape Deck Section ························· 35
7-14. Printed Wiring Board   Panel Section ······························· 36
7-15. Schematic Diagram   Panel Section ································· 37
7-16. Printed Wiring Board   AC Sec Standby Section ············· 38
7-17. Schematic Diagram   AC Sec Standby Section ················ 39
7-18. Printed Wiring Board   Leaf SW Section ························· 40
7-19. Schematic Diagram   Leaf SW Section ···························· 40
7-20. Printed Wiring Board   CD SW Section ··························· 41
7-21. Schematic Diagram   CD SW Section ······························ 41
7-22. Printed Wiring Board   Video Section ······························ 42
7-23. Schematic Diagram   Video Section (1/3) ························ 43
7-24. Schematic Diagram   Video Section (2/3) ························ 44
7-25. Schematic Diagram   Video Section (3/3) ························ 45
7-26. IC Block Diagrams ··························································· 46
7-27. IC PIN Function Description ············································ 49

8-1.

Case Section ····································································· 58

8-2.

Front Panel Section ·························································· 59

8-3.

Chassis Section ································································· 60

8-4.

CD Mechanism Deck Section-1 (CDM38L-5BD34L) ···· 61

8-5.

CD Mechanism Deck Section-2 (CDM38L-5BD34L) ···· 62

8-6.

Base Unit Section (BU-5BD32L) ····································· 63

8-7.

TC Mechanism Section-1(TCM-230AWR2/230PWR2) · 64

8-8.

TC Mechanism Section-2(TCM-230AWR2/230PWR2) · 65

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