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HCD-MD555
US Model
AEP Model
UK Model
E Model
Tourist Model
SERVICE MANUAL
MINI Hi-Fi COMPONENT SYSTEM
MICROFILM
Model Name Using Similar Mechanism
NEW
CD Section
CD Mechanism Type
CDM53-K1BD33
Optical Pick-up Type
KSM-213BFN/C2NP
Model Name Using Similar Mechanism
NEW
MD Section
MD Mechanism Type
MDM-C1E
Base Unit Type
MBU-C1E
Optical Pick-up Type
KSM-260A/J1N
· This set is the Amplifier, CD player,
MD Deck and Tuner section in
DHC-MD555.
-- Continued on next page --
SPECIFICATIONS
Manufactured under license from Dolby Laboratories
Licensing Corporation.
"DOLBY" the double-D symbol
a "AC-3" and "PRO
LOGIC" are trademarks of Dolby Laboratories
Licensing Corporation.


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-- 2 --
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
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.
NOTES ON LASER DIODE EMISSION CHECK
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.
Notes on chip component replacement
· Never reuse a disconnected chip component.
· Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
Flexible Circuit Board Repairing
· Keep the temperature of the soldering iron around 270 °C dur-
ing 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
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK
! OR DOTTED LINE WITH
MARK
! ON THE SCHEMATIC DIAGRAMS AND IN THE PARTS
LIST ARE CRITICAL TO SAFE OPERATION. REPLACE THESE
COMPONENTS WITH SONY PARTS WHOSE PART NUMBERS
APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS
PUBLISHED BY SONY.


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-- 3 --
CAUTION
Use of controls or adjustments or performance of
procedures other than those specified herein may
result in hazardous radiation exposure.
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.
The following caution label is located inside the unit.
MODEL IDENTIFICATION
­ BACK PANEL ­
SAFETY CHECK-OUT
After correcting the original service problem, perform the following
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" 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 2 V AC range are suitable. (See Fig. A)
Earth Ground
AC
voltmeter
(0.75V)
1.5k
0.15
µF
Fig. A. Using an AC voltmeter to check AC leakage.
To Exposed Metal
Parts on Set
COMPACT DISC DECK RECEIVER
SERIAL
MODEL NO.
HCD-MD555
MADE IN
NO.
JAPAN
AC: 230V ~ 50/60Hz 90W: AEP, UK model
AC: 110 ­ 120/220 ­ 240V ~ 50/60Hz 90W
: Singapore, Malaysia, Hong Kong, Tourist model
AC: 120V 60Hz 90W: US model


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-- 4 --
TABLE OF CONTENTS
1. SELF-DIAGNOSIS FUNCTION ·································· 5
2. SERVICE NOTE ······························································· 8
3. GENERAL ········································································ 12
4. DISASSEMBLY
4-1.
Back Panel ········································································ 25
4-2.
Mechanism (MDM-C1E) ················································· 25
4-3.
SP Board, Amp Board, Reg Board ··································· 26
4-4.
Front Panel ······································································· 26
4-5.
Power Key Board, LED Board, Panel Board ··················· 27
4-6.
Power Transformer (T960), Trans-A/B/C/D Board ········· 27
4-7.
CD Mechanism (CDM53-K1BD33) ································ 28
4-8.
Escutcheon, Chassis (Top) ··············································· 29
4-9.
Chassis (Elevator) New ···················································· 30
4-10. Motor (Head) Assy (M905), Head Relay Board ·············· 30
4-11. MD Base Unit (MBU-C1E) ············································· 31
4-12. BD Board ·········································································· 31
4-13. Over Light Head (HR901) ················································ 32
4-14. MD Optical Pick-up Block (KMS-260A/J1N) ················· 32
4-15. CD Optical Pick-up Block (KSS-213BA/F-NP) ·············· 33
4-16. Fitting Base (Guide/Magnet) Assy ··································· 33
4-17. Tray (Sub) ········································································· 34
4-18. Chassis (Mold B), Stocker, Slider (Selection) ·················· 34
4-19. How to Assembly The Gears ············································ 35
4-20. How to Attach The Slider (Selection) ······························ 35
4-21. How to Attach The Stocker ·············································· 36
4-22. How to Attach The Chassis (Mold B) ······························ 36
5. TEST MODE ···································································· 37
6. ELECTRICAL ADJUSTMENT ·································· 43
7. DIAGRAMS
7-1.
Block Diagrams ································································ 53
· MD Section ···································································· 53
· CD Section····································································· 55
· Audio Section ································································ 57
· Power Section ································································ 59
7-2.
Circuit Boards Location ··················································· 61
7-3.
Schematic Diagram -- CD Section -- ····························· 63
7-4.
Printed Wiring Board -- CD Section -- ·························· 65
7-5.
Schematic Diagram --Motor Section -- ························· 67
7-6.
Printed Wiring Board -- Motor Section -- ······················ 69
7-7.
Printed Wiring Board -- MD Section -- ························· 71
7-8.
Schematic Diagram -- MD Section (1/2) -- ··················· 73
7-9.
Schematic Diagram -- MD Section (2/2) -- ··················· 75
7-10. Schematic Diagram -- Rds Section -- ···························· 77
7-11. Printed Wiring Board -- Rds Section -- ························· 78
7-12. Schematic Diagram -- Relay Section -- ························· 79
7-13. Printed Wiring Board -- Relay Section -- ······················ 81
7-14. Printed Wiring Board -- Main Section -- ······················· 83
7-15. Schematic Diagram -- Main Section (1/3) -- ················· 85
7-16. Schematic Diagram -- Main Section (2/3) -- ················· 87
7-17. Schematic Diagram -- Main Section (3/3) -- ················· 89
7-18. Schematic Diagram -- Amp Section -- ··························· 91
7-19. Printed Wiring Board -- Amp Section -- ························ 93
7-20. Schematic Diagram -- Panel Section -- ························· 95
7-21. Printed Wiring Board -- Panel Section ···························· 97
7-22. Schematic Diagram -- Power Section -- ························ 99
7-23. Printed Wiring Board -- Power Section -- ··················· 101
7-24. IC Block Diagrams ························································· 105
7-25. IC Pin Function Description ··········································· 111
8. EXPLODED VIEWS
8-1.
Main Block ····································································· 123
8-2.
Back Panel Block ··························································· 124
8-3.
MD Mechanism Deck-1 (MDM-C1E) ··························· 125
8-4.
MD Mechanism Deck-2 (MDM-C1E) ··························· 126
8-5.
MD Base Unit (MBU-C1E) ··········································· 127
8-6.
CD Mechanism Deck-1 (CDM53-K1BD33) ················· 128
8-7.
CD Mechanism Deck-2 (CDM53-K1BD33) ················· 129
8-8.
Optical Block (BU-K1BD33) ········································· 130
9. ELECTRICAL PARTS LIST ····································· 131


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-- 5 --
SECTION 1
SELF-DIAGNOSIS FUNCTION
OPERATING THE ERROR HISTORY MODE
Note: The self-diagnosis function is performed using the "error history display mode" in the test mode. The following procedure describes
only the minimum required operating procedure to enter the error history mode. Therefore be careful not to enter any other modes by
mistake. If you have entered any other modes by mistake, press the MENU/NO button and exit the mode.
1. Press ENTER/YES , NAME EDIT and MD3 .
(If the [Check] is not displayed, press the MENU/NO or
p to let [Check] appear.)
2. Turn the MULTI JOG to display "[Service]", and press the ENTER/YES button.
3. Turn the MULTI JOG to display "ERR DP MODE" .
4. Press the ENTER/YES button to enter the error history mode and the message "total rec" appears.
5. Select the item to be displayed or to be executed using the MULTI JOG .
6. When you want to display or execute the selected item, press the MULTI JOG .
7. If you press the MULTI JOG again, the display returns to step 4.
8. You can exit the error history mode by pressing the MENU/NO button. The message "ERR DP MODE" is displayed.
9. You can exit the test mode by pressing the REPEAT . Then the HCD-MD555 enters the standby state, the disc is ejected, and the display
exits the test mode.
MD SECTION