Sony MDS-JA50ES Service Manual

MDS-JA50ES

SERVICE MANUAL

Photo: GOLD

Model Name Using Similar Mechanism NEW MD Mechanism Type MDM-4A Base Unit Type MBU-2B Optical Pick-up Type KMS-210A/J-N

SPECIFICATIONS

US Model

AEP Model

UK Model

MICROFILM

MINIDISC DECK

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CAUTION

SAFETY CHECK-OUT

After correcting the original service problem, perform the following 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 A C leakag e. 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). 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 V OM or battery-operated A C v oltmeter. 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 2V AC range are suitable. (See Fig. A)

To Exposed Metal Parts on Set

Danger of explosion if battery is incorrectly replaced. Replace only with the same or equivalent type recommended by the equipment manufacturer. Discard used batteries according to manufacture’s instructions.

ADVARSEL!

Lithiumbatteri - Eksplosionsfare ved fejlagtig håndtering.

Udskiftning må kun ske med batteri af samme fabrikat og type.

Levér det brugte batteri tilbage til leverandøren.

ADVARSEL

Eksplosjonsfare ved feilakting skifte av batteri.

Benytt samme batteritype eller en tilsvarende type anbefalt av

apparatfabrikanten.

Brukte batterier katterier kasseres i henhold til fabrikantens

VARNIG

Explosionsfara vid felaktigt batteribyte. Använd samma batterityp eller en likvärdig typ som rekommenderas av apparattillverkaren. Kassera använt batteri enligt gällande föreakrifter.

VAROITUS

Parist voi räjähtää, jos se on virheellisesti asennettu. V aihda paristo ainoastaan laite valmistajan suosittelemaan tyyppiin. Hävitä käytetty paristo valmistajan ohjeiden mukaisesti.

0.15µF

1.5k

Ω

Earth Ground

AC voltmeter (0.75V)

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

SAFETY-RELATED COMPONENT WARNING !!

COMPONENTS IDENTIFIED BY MARK ! OR DO TTED 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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The laser component in this product is capable of emitting radiation exceeding the limit for Class 1.

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

TABLE OF CONTENTS

1. SERVICING NOTE

.......................................................... 4

2. GENERAL .......................................................................... 7

3. DISASSEMBLY

3-1. Tray Assembly .................................................................... 26

3-2. Bracket (Motor) ASSY ....................................................... 27

3-3. Holder ASSY ...................................................................... 27

3-4. Base Unit.............................................................................28

3-5. HMOT Board and HLIM Board ......................................... 28

4. TEST MODE ..................................................................... 29

The following caution label is located inside the unit.

CAUTION

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

Notes on chip component replacement

• Never reuse a disconnected chip component.

• Notice that the minus side of a tantalum capacitor may be damaged by heat.

Flexible Circuit Board Repairing

• 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.

MODEL IDENTIFICATION — BACK PANEL —

Parts No.

5. ELECTRICAL ADJUSTMENTS ............................... 32

6. DIAGRAMS

6-1. Brock Diagrams

• BD Section ....................................................................... 37

• Digital Section ................................................................. 39

• Audio Section .................................................................. 41

• Power Section .................................................................. 43

6-2. Circuit Boards Location ...................................................... 44

6-3. Waveforms ......................................................................... 45

6-4. Printed Wiring Board — BD Section —.............................47

6-5. Schematic Diagram — BD Section — ............................... 49

6-6. Schematic Diagram — Digital Section —.......................... 52

6-7. Printed Wiring Board — Digital Section — ....................... 55

6-8. Printed Wiring Board — MD Section —............................ 57

6-9. Schematic Diagram — MD Section — .............................. 58

6-10. Printed Wiring Board — D Out, D Vol Section — .......... 59

6-11. Schematic Diagram — D Out, D Vol Section — ............. 60

6-12. Printed Wiring Board — DA Section — .......................... 61

6-13. Schematic Diagram — DA Section —.............................63

6-14. Printed Wiring Board — AD Section — .......................... 65

6-15. Schematic Diagram — AD Section —.............................67

6-16. Printed Wiring Board — Panel Section —....................... 69

6-17. Schematic Diagram — Panal Section — ......................... 71

6-18. Printed Wiring Board — Power Section — ..................... 73

6-19. Schematic Diagram — Power Section — ........................ 75

6-20. IC Block Diagrams ........................................................... 77

6-21. IC Pin Functions ............................................................... 84

7. EXPLODED VIEWS

7-1. Main Section ..................................................................... 100

7-2. Chassis Section ................................................................. 101

7-3. Front Panel Section 1 ........................................................ 102

7-4. Front Panel Section 2 ........................................................ 103

7-5. Mechanism Section 1 (MDM-4A) .................................... 104

7-6. Mechanism Section 2 (MDM-4A) .................................... 105

7-7. Mechanism Section 3 (MDM-4A) .................................... 106

7-8. Base Unit Section (MBU-2B) ........................................... 107

4-987-511-2 : AEP, UK, German model 4-987-511-3 : US model

8. ELECTRICAL PARTS LIST ...................................... 108

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SECTION 1

SERVICING NOTE

HOW TO OPEN THE DISC TRAY WHEN POWER SWITCH TURNS OFF

1 Remove the fourteen screws (BVTT 3x8) from the bottom plate. 2 Remove the bottom plate. 3 Rotate the pulley gear in the arrow direction A, and open the tray assembly in the arrow direction B.

Pully gear

Tray assembly

FORCED RESET

The system microprocessor can be reset in the following way. Use these methods when the unit cannot be operated normally due to the overrunning of the microprocessor, etc.

Method 1:

Set TP (S.RST) of the DIG board to ground momentarily.

[DIG board] (Side A)

CN203

(S.RST)

C206

IC202

Method 2:

Disconnect the power plug, and short-circuit CN905 of the PW board with a pair of tweezers, etc.

[PW board] (Component Side)

CN901

CN905 (RESET)

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RETRY CAUSE DISPLAY MODE

• In this test mode, the causes for retry of the unit during recording can be displayed on the fluorescent display tube. This is useful for locating the faulty part of the unit.

• The retry cause, number of retries, and number of retry errors are displayed. Each is displayed in hexadecimal number.

Method:

1. Load a recordable disc whose contents can be erased into the unit.

2. Press the p button, §OPEN/CLOSE button, DISPLAY/CHAR button simultaneously.

3. Press the r button, and start recording.

4. The ## value increases with each retry. If an error occurs after a retry, the @@ count will also increase.

5. To exit the test mode, press the TIME button.

Fig. 1 Reading the Test Mode Display

R.T s ∗ ∗ c # # e @@

Fluorescent Display Tube Signs

∗ ∗ : Cause of retry

# # : Number of retries @@: Number of retry errors

All three displays above are in hexadecimal numbers.

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Reading the Retry Cause Display

Higher Bits Lower Bits

Hexadecimal

Bit

Binary

*1 Some displays are not used depending on the microprocessor version.

Reading the Display:

Convert the hexadecimal display into binary display. If more than two causes, they will be added.

Example

When 42 is displayed: Higher bit : 4 = 0100 n b6 Lower bit : 2 = 0010 n b1 In this case, the retry cause is combined of “spindle is slow” and “ader5”.

84218421

b7 b6 b5 b4 b3 b2 b1 b0

00000001

00000010

00000100 00001000 00010000 00100000 01000000 10000000

Hexa-

decimal

04 08 10 20 40 80

Cause of Retry Occurring conditions

shock *1

ader5

Discontinuous address (Not used) FCS incorrect IVR rec error Spindle is slow Access fault

When more than 3.5 shocks are detected When ADER was counted more than five times continuously When ADIP address is not continuous (Not used) When not in focus When ABCD signal level exceeds the specified range When spindle rotation is detected as slow When access operation is not performed normally

When A2 is displayed: Higher bit : A = 1010 n b7+b5 Lower bit : 2 = 0010 n b1

The retry cause in this case is combined of “access fault”, “IVR rec error”, and “ader5”.

Hexadecimal n Binary Conversion Table

Hexadecimal Binary Hexadecimal Binary

0 1 2 3 4 5 6 7

Reference:

In this test mode, when the · button is pressed, and the disc is played back, the “PLAYBACK MODE” is set. The display becomes as shown in Fig. 2. The playback mode is not used in particular during servicing.

44 ¢¢¢¢¢¢ p

0000 0001 0010 0011 0100 0101 0110 0111

9 A B C D E

1000 1001 1010 1011 1100 1101 1110 1111

Fig. 2 Display during Playback Mode

4 : Parts No. (Name of area named on TOC) ¢¢¢¢¢¢ : Address (Physical address on disc) p : Track mode (Copyright information of each part, information on copyright, etc.)

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