PMC-MD55 - Sony Audio Service Manual (repair manual)

US Model

Canadian Model

AEP Model

UK Model

CD

Model Name Using Similar Mechanism

NEW

Section

CD Mechanism Type

KSM-213CGP

Optical Pick-up Name

KSS-213C

MD

Model Name Using Similar Mechanism

MDS-JB920

Section

MD Mechanism Type

MDM-5A

Base Unit Name

MBU-5A

Optical Pick-up Name

KMS-260A

U.S. and foreign patents licensed form Dolby Laboratories
Licensing Corporation.

– Continued on next page –

2005L05-1
© 2005.12

87.5 - 108 MHz (AEP, UK)

(US, Canadian)

(US, Canadian)

MW: 531 - 1,602 kHz (AEP, UK)
LW: 153 - 279 kHz (AEP, UK)

AM (MW/LW): Loop antenna

– 2 –

..............................................

3

Playing a CD ..................................................................

6

Recording a Whole CD ..................................................

6

Playing an MD ...............................................................

7

Listening to the radio .....................................................

7

Setting the Clock ............................................................

8

Hooking up the System ..................................................

8

........................................................

9

............................................................. 15

Tuner Section ................................................................. 19
MD Section .................................................................... 21
CD Section ..................................................................... 28
Display Section .............................................................. 30

6-1. Block Diagram  – TUNER Section – ............................ 31
6-2

Block Diagram  – MD Section – ................................... 34

6-3. Block Diagram  – CD Section – .................................... 37
6-4. Block Diagram

– FUNCTION SELECT/PANEL Section – ................... 40

6-5. Block Diagram

– POWER AMP/POWER SUPPLY Section – .............. 43

6-6. Block Diagram  – SUPER WOOFER Section – ........... 45
6-7. Printed Wiring Board  – TUNER Section – .................. 49
6-8. Schematic Diagram  – TUNER Section – ..................... 51
6-9. Schematic Diagram  – BD Section – ............................. 53
6-10. Printed Wiring Boards  – BD Section – ........................ 57
6-11. Printed Wiring Board  – DG Section – .......................... 59
6-12. Schematic Diagram  – DG Section – ............................. 61
6-13. Printed Wiring Boards  – MAIN Section – ................... 64
6-14. Schematic Diagram  – MAIN (CD) Section – .............. 67
6-15. Schematic Diagram

– MAIN (SYSTEM CONTROL) Section – .................. 70

6-16. Schematic Diagram

– MAIN (FUNCTION SELECT) Section – .................. 73

6-17. Printed Wiring Board  – AUDIO/JACK Section – ........ 75
6-18. Schematic Diagram  – AUDIO/JACK Section – .......... 77
6-19. Schematic Diagram  – CD MOTOR Section – ............. 79
6-20. Printed Wiring Board  – CD MOTOR Section – .......... 81
6-21. Printed Wiring Board

– CD OPEN/CLOSE Section – ...................................... 82

6-22. Schematic Diagram  – CD OPEN/CLOSE Section – ... 83
6-23. Printed Wiring Boards  – PANEL Section – ................. 86
6-24. Schematic Diagram  – PANEL Section – ...................... 89
6-25. Printed Wiring Boards

– POWER AMP/POWER Section – .............................. 91

6-26. Schematic Diagram

– POWER AMP/POWER Section – .............................. 93

6-27. Printed Wiring Boards

– SUPER WOOFER Section – ...................................... 95

6-28. Schematic Diagram

– SUPER WOOFER Section – ...................................... 97

6-29. IC Pin Function Description .......................................... 108

............................................... 118

.............................. 128

!

!

Maximum power output

7 W+7 W

0

230 V AC, 50 Hz (AEP, UK)

(US, Canadian)

(MW/LW)

– 3 –

After correcting the original service problem, perform the follow-
ing 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.

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 microamperes).
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” indica-
tion is 0.75 V, so analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
amples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V AC range are suit-
able.  (See Fig. A)

1.5 k

Ω

0.15 

µ

F

AC
voltmeter
(0.75 V)

To Exposed Metal
Parts on Set

Earth Ground

On repairing CD section, playing a disc without the CD lid, use
Chuck Plate Jig.
• Code number of Chuck Plate Jig: X-4918-255-1

The laser diode in the optical pick-up block may suffer electro-
static 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 emis-
sion, observe from more than 30 cm away from the objective lens.

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

aged by heat.

• 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.

CAUTION

Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous ra-
diation 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.

– 4 –

The special jig (J-2501-149-A) is useful for checking the waveform of the BD board. The names of terminals and the checking items to be
performed are shown as follows.

GND : Ground
I+3V : For measuring IOP (Check the deterioration of the optical pick-up laser)
IOP : For measuring IOP (Check the deterioration of the optical pick-up laser)
TEO : TRK error signal (Traverse adjustment)
VC

: Reference level for checking the signal

RF

: RF signal (Check jitter)

RF
VC
TEO

for MDM-5

IOP
I+3V

VC
RF
TEO
IOP
I+3V
GND

VC

RF

TEO

IOP

I+3V

GND

1

5

1

6

for MDM-3 

CN110

RF

5P Connector

6P connector

VC

TEO

IOP

I+3V

GND

Mechanism deck