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Model Name Using Similar Mechanism
MDS-S37
MD Mechanism Type
MDM-3B
Optical Pick-up Type
KMS-260A/J1N
MDS-S38
SERVICE MANUAL
US Model
Canadian Model
AEP Model
UK Model
E Model
MINIDISC DECK
MICROFILM
Photo: Black
SPECIFICATIONS


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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.
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.
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 ra-
diation exposure.
The laser component in this product is
capable of emitting radiation exceeding
the limit for Class 1.
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 IDENTIFIÉS 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 PIÈCES SONY DONT LES NUMÉROS
SONT DONNÉS DANS CE MANUEL OU DANS LES
SUPPLÉMENTS PUBLIÉS PAR SONY.


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To Exposed Metal
Parts on Set
0.15µF
1.5k
AC
voltmeter
(0.75V)
Earth Ground
SAFETY CHECK-OUT
After correcting the original service problem, perform the follow-
ing 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). Leak-
age 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 pas-
sive VOM that is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are suitable. (See Fig. A)
Fig. A. Using an AC voltmeter to check AC leakage.
MODEL IDENTIFICATION
-- BACK PANEL --
Parts No.
4-989-525-1
4-989-525-2
4-989-525-3
4-989-525-4
4-989-525-5
4-989-525-6
4-989-525-7
Parts No.
Model
US model
Canadian model
AEP model
UK model
Singapore model
Hong Kong model
Tourist model
Product country
MALAYSIA
MALAYSIA
MALAYSIA
MALAYSIA
MALAYSIA
MALAYSIA
JAPAN
TABLE OF CONTENTS
1. SERVICING NOTE .......................................................... 5
2. GENERAL .......................................................................... 8
3. DISASSEMBLY
3-1. Front Panel ......................................................................... 22
3-2. Back Panel and Main Board ............................................... 23
3-3. Bracket (T), (L) and (R) ...................................................... 24
3-4. BD Board ........................................................................... 24
3-5. SUB Chassis ........................................................................ 25
3-6. Shutter Assembly ................................................................ 25
3-7. Over Write Head ................................................................. 26
3-8. Slider Complete Assembly .................................................. 27
4. TEST MODE ..................................................................... 28
5. ELECTRICAL ADJUSTMENTS ............................... 31
6. DIAGRAMS
6-1. Circuit Boards Location ...................................................... 36
6-2. Block Diagrams
· BD Section ....................................................................... 37
· Main Section .................................................................... 39
6-3. Printed Wiring Board -- BD Section -- ............................. 42
6-4. Schematic Diagram -- BD Section -- ............................... 45
6-5. Schematic Diagram -- Main Section -- ............................ 49
6-6. Printed Wiring Board -- Main Section -- .......................... 53
6-7. Schematic Diagram -- Panel Section -- ............................ 55
6-8. Printed Wiring Board -- Panel Section -- ......................... 57
6-9. IC Block Diagrams ............................................................. 60
6-10. IC Pin Functions ............................................................... 65
7. EXPLODED VIEWS
7-1. Main Section ....................................................................... 74
7-2. Front Panel Section ............................................................. 75
7-3. Mechanism Deck Section (1) (MDM-3B) .......................... 76
7-4. Mechanism Deck Section (2) (MDM-3B) .......................... 77
8. ELECTRICAL PARTS LIST ........................................ 78


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SECTION 1
SERVICING NOTE
JIG FOR CHECKING BD BOARD WAVEFORM
The special jig (J-2501-124-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.
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)
IOP
I + 3V
TEO
VC
RF
Mechanism deck
CN110
Jig
(J-2501-124-A)
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 :
Disconnect the power plug, short-circuit JW143 and JW164 on the main board with a pincette or etc.
[MAIN BOARD] (Component Side)
S301
CN302
JW143
JW164
C001


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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 data amount stored in D RAM, number of retries, and retry cause are displayed. Each is displayed in hexadecimal number.
· The display of the D RAM data amount enables data reading, accumulation, ejection, and writing to be performed smoothly. If writing is
not smooth, data may decrease considerably.
Method:
1. Load a recordable disc whose contents can be erased into the unit.
2. Press the EDIT/NO button several times to display "All Erase?" on the fluorescent display tube.
3. Press the YES button.
4. When "All Erase??" is displayed on the fluorescent display tube, the numbers on the music calendar will start blinking.
5. Press the YES button to display "Complete", and press the
p button immediately and continue pressing for about 10 seconds.
6. When the "TOC" displayed on the fluorescent display tube goes off, release the
p button.
7. Press the
r button to start recording.
8. Press the DISPLAY/CHAR button to display the test mode (Fig. 1), and check the display.
9. The Rt value increases with each retry. If an error occurs after a retry, "Retry Error" will be displayed, and the number of retries counted
will be set back to 0.
10. To exit the test mode, press the POWER button. Turn OFF the power, and after "TOC" disappears, disconnect the power plug from the
outlet.
Fig. 1 Reading the Test Mode Display
SC @@
Rt # #
Fluorescent Display Tube Signs
@@ : Displays the DRAM memory amount when at all times.
# #
: Displays the number of retries. When a retry error occurs, the number will be set back to 0.
* *
: Cause of retry
All three displays above are in hexadecimal numbers.