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US Model
Canadian Model
AEP Model
UK Model
SERVICE MANUAL
MINIDISC DECK
MICROFILM
Model Name Using Similar Mechanism
MDS-JA50ES
MD Mechanism Type
MDM-4B
Base Unit Type
MBU-2B
Optical Pick-up Type
KMS-210A/J-N
MDS-JA30ES
SPECIFICATIONS
-- Continued on next page --
U.S. and foreign patents licensed from Dolby Laboratories
Licensing Corporation.
Photo: GOLD


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-- 2 --
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.
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFÉS PAR UNE MARQUE
! SUR LES
DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES PIÈCES SONT
CRITIQUES POUR LA SÉCURITÉ DE FONCTIONNEMENT. NE
REMPLACER CES COMPOSANTS QUE PAR DES PIÈSES SONY
DONT LES NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPÉMENTS PUBLIÉS PAR SONY.
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 AC leakage. 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
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 2V AC range are suitable. (See
Fig. A)
SAFETY CHECK-OUT
CAUTION
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.
Vaihda paristo ainoastaan laitevalmistajan suosittelemaan tyyppiin.
Hävitä käytetty paristo valmistajan ohjeiden mukaisesti.
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


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-- 3 --
This appliance is classified as a CLASS 1
LASER product. The CLASS 1 LASER
PRODUCT MARKING is located on the
rear exterior.
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.
The laser component in this product is
capable of emitting radiation exceeding
the limit for Class 1.
MODEL IDENTIFICATION
-- BACK PANEL --
Parts No.
4-992-959-1
: AEP, UK, German model
4-992-959-2
: US model
4-992-959-3
: Canadian model
TABLE OF CONTENTS
1.
SERVICING NOTE ······················································ 4
2.
GENERAL ······································································ 7
3.
DISASSEMBLY
3-1.
Tray Assembly ···································································· 8
3-2.
Bracket (Motor) ASSY ······················································· 9
3-3.
Holder ASSY ······································································ 9
3-4.
Base Unit ·········································································· 10
3-5.
HMOT Board and HLIM Board ······································· 10
4.
TEST MODE ································································ 11
5.
ELECTRICAL ADJUSTMENTS ··························· 14
6.
DIAGRAMS
6-1.
BD Section ······································································· 19
6-2.
Digital Section ·································································· 21
6-3.
Audio Section ··································································· 23
6-4.
Power Section ··································································· 25
6-5.
Circuit Boards Location ··················································· 26
6-6.
Printed Wiring Board -- BD Section -- ·························· 28
6-7.
Schematic Diagram -- BD Section -- ····························· 31
6-8.
Schematic Diagram -- Digital Section -- ······················· 35
6-9.
Printed Wiring Board -- Digital Section -- ···················· 39
6-10. Printed Wiring Board -- Audio Section -- ······················ 42
6-11. Schematic Diagram -- Audio Section -- ························· 45
6-12. Schematic Diagram -- Power Section -- ························ 48
6-13. Schematic Diagram -- Panel Section -- ························· 51
6-14. Printed Wiring Board -- Panel Section -- ······················· 53
6-15. IC Block Diagrams ··························································· 56
6-16. IC Pin Functions ······························································· 61
7.
EXPLODED VIEWS
7-1.
Main Section ····································································· 73
7-2.
Chassis Section ································································· 74
7-3.
Front Panel Section 1 ······················································· 75
7-4.
Front Panel Section 2 ······················································· 76
7-5.
Mechanism Section 1 (MDM-4B) ···································· 77
7-6.
Mechanism Section 2 (MDM-4B) ···································· 78
7-7.
Mechanism Section 3 (MDM-4B) ···································· 79
7-8.
Base Unit Section (MBU-2B) ·········································· 80
8.
ELECTRICAL PARTS LIST ··································· 81


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-- 4 --
SECTION 1
SERVICING NOTE
HOW TO OPEN THE DISC TRAY WHEN POWER SWITCH TURNS OFF
1 Remove the sixteen screws (BVTT 3
×8) 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.
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 2:
Disconnect the power plug, and short-circuit CN905 of the PW board
with a pair of tweezers, etc.
[PW board] (Component Side)
CN905
(RESET)
CN901
Method 1:
Set TP (S.RST) of the DIG board to ground momentarily.
[DIG board] (Side A)
TP
(S.RST)
CN203
C206
IC202
Pully gear
Tray assembly
B
A


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-- 5 --
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.