HCD-GX450, MHC-GX450 - Sony Audio Service Manual (repair manual). Page 3

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This appliance is classified as a CLASS 1 LASER product. The
CLASS 1 LASER PRODUCT MARKING is located on the rear
exterior.

Laser component in this product is capable
of emitting radiation exceeding the limit for
Class 1.

Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous radiation
exposure.

• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be

damaged by heat.

• Keep the temperature of 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.

The laser diode in the optical pick-up block may suffer electrostatic
break-down because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.

The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pick-
up block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.

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3-1. Cover (Top) ····································································· 9
3-2. CD Door ·········································································· 9
3-3. Front Panel Section ······················································· 10
3-4. CD Mechanism Deck (CDM74-F1BD81) ···················· 10
3-5. Tape Mechanism Deck, Game Jack Board ··················· 11
3-6. PANEL Board ······························································· 11
3-7. Back Panel Section, SUB-TRANS Board ···················· 12
3-8. Power  Transformer ······················································· 12
3-9. MAIN Board ································································· 13
3-10. SUB-WOOFER Board ················································ 13
3-11. AMP Board ································································· 14
3-12. BD81A Board ····························································· 14
3-13. CONNECT Board ······················································· 15
3-14. DRIVER Board, SW Board ········································ 15
3-15. Optical Pick-up (KSM-215DCP/C2NP) ····················· 16
3-16. SENSOR Board ·························································· 16
3-17. MOTOR (TB) Board ··················································· 17
3-18. MOTOR (LD) Board ·················································· 17

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5-1. Block Diagrams – PANEL Section – ···························· 22

– MAIN Section – ······················································· 23
– BD/DRIVER Section – ············································ 24
– SUB-WOOFER Section – ········································ 25

5-2. Printed Wiring Board  – BD81A Section – ··················· 26
5-3. Schematic Diagram  – BD81A Section – ····················· 27
5-4. Printed Wiring Board

– CD MECHANISM Section – ··································· 28

5-5. Schematic Diagram  – CD MECHANISM Section – ··· 29
5-6. Printed Wiring Board  – MAIN Section – ···················· 30
5-7. Schematic Diagram  – MAIN Section (1/2) – ·············· 31
5-8. Schematic Diagram  – MAIN Section (2/2) – ·············· 32
5-9. Printed Wiring Board  – PANEL COMB Section – ······ 33
5-10. Schematic Diagram  – PANEL COMB Section – ······ 34
5-11. Printed Wiring Board  – SUB-WOOFER Section – ··· 35
5-12. Schematic Diagram

– SUB-WOOFER Section – ········································ 36

5-13. Printed Wiring Board  – PANEL Section – ················· 37
5-14. Schematic Diagram  – PANEL Section (1/2) – ·········· 38
5-15. Schematic Diagram  – PANEL Section (2/2) – ·········· 39
5-16. Printed Wiring Board  – TRANS Section – ················ 40
5-17. Printed Wiring Board  – AMP Section – ····················· 41
5-18. Schematic Diagram  – AMP POWER Section – ········ 42
5-19. IC Pin Function Description ······································· 46

6-1. MAIN Section ······························································· 51
6-2. Front Panel Section ······················································· 52
6-3. MAIN Board Section ···················································· 53
6-4. CD Mechanism Deck Section -1 (CDM74-F1BD81) ··· 54
6-5. CD Mechanism Deck Section -2 (CDM74-F1BD81) ··· 55

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