Sony M-640V - Microcassette Recorder User manual

SERVICE MANUAL
MICROCASSETTETM-CORDER
US Model
M-645V/647V
East European Model
E Model
Chinese Model
Tourist Model
M-640V
SPECIFICATIONS
M-640V/645V/647V
Ver 1.0 2001.02
9-873-059-11 Sony Corporation
2001B0500-1 Audio Entertainment Group
C2001.2 General Engineering Dept.
Model Name Using Similar Mechanism M-530V
Tape Transport Mechanism Type MZ-530V-99

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M-640V/645V/647V
TABLE OF CONTENTS
1. GENERAL ................................................................... 3
2. DISASSEMBLY
2-1. Disassembly Flow ........................................................... 4
2-2. Lid Assy, Cassette ........................................................... 4
2-3. Lid, Battery Case ............................................................ 5
2-4. Cabinet (Rear) Assy ........................................................ 5
2-5. MAIN Board ................................................................... 6
2-6. Mechanism Deck (MZ-530V-99) ................................... 6
2-7. LED Unit ......................................................................... 7
2-8. Head, Ceramic (HRPE901)............................................. 7
3. MECHANICAL ADJUSTMENTS ....................... 8
4. ELECTRICAL ADJUSTMENTS......................... 8
5. DIAGRAMS
5-1. Block Diagram ................................................................ 11
5-2. Printed Wiring Board ...................................................... 12
5-3. Schematic Diagram ......................................................... 13
6. EXPLODED VIEWS
6-1. Cabinet Section ............................................................... 14
6-2. Main Group Section ........................................................ 15
6-3. Mechanism Deck Section (MZ-530V-99) ...................... 16
7. ELECTRICAL PARTS LIST ............................... 17
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0OR DOTTED
LINE WITH MARK 0ON 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 PUB-
LISHED BY SONY.
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.
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.

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M-640V/645V/647V
SECTION 1
GENERAL This section is extracted from
instruction manual.

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M-640V/645V/647V
• This set can be disassembled in the order shown below.
2-1. DISASSEMBLY FLOW
SECTION 2
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given.
2-2. LID ASSY, CASSETTE
Set Lid Assy,
Cassette
Cabinet (rear)
Assy Main Board Mechanism Deck
(MZ-530V-99)
Head,
Ceramic (HRPE901
)
LED
Unit
Lid,
Battery Case
2 Stop the “lid assy, cassette”
halfway.
1
3
4
precision screwdriver
or equivalent
cabinet (front)
lid assy,
cassette
top view
precision screwdriver
or equivalent
Note:When removing the cassette lid, put cloth on the end of a
screwdriver or use a polyacetal driver to avoid damage to
the cabinet.
9 lid assy, cassette
5 claw
8
6
boss
7 boss

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M-640V/645V/647V
2-3. LID, BATTERY CASE
2-4. CABINET (REAR) ASSY
Note:When installing, fit the knobs and switches.
3 two claws
4 lid, battery case
2
1
2
1 two screws (1.7x16)
3 screw (B1.7x5), tapping
2 two screws (1.7x16)
5 claw
4 two claws
switch
switch
knob
knob
6 cabinet (rear) assy

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M-640V/645V/647V
2-5. MAIN BOARD
2-6. MECHANISM DECK (MZ-530V-99)
9 lock, serrat IB
0 lock, serrat IB
8 mic assy
qa MAIN board
3 Remove four solders.
6 Remove four solders.
7 Remove the solder.
2 Remove two solders.
1 Remove two solders.
4 Remove two solders.
5 Remove two solders.
4 button (STOP)
2 button (REC)
belt (flywheel)
belt (counter, tape)
• How to apply the belts
1
3 button (PLAY)
5 mechanism deck
(MZ-530V-99)
M901
flywheel assy

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M-640V/645V/647V
2-7. LED UNIT
2-8. HEAD, CERAMIC (HRPE901)
2 bracket (LED)
3 LED unit
1 screw (1.7), tapping
1 claw
3 screw (M1.4x4.5), lookin
g
4 screw (M1.4), special head
2 arm (pinch roller) assy
5 head, ceramic
(HRPE901)

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M-640V/645V/647V
SECTION 3
MECHANICAL ADJUSTMENTS SECTION 4 ELECTRICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback/erase head pinch roller
rubber belts capstan
2. Demagnetize the record/playback/erase head with a head
demagnetizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
Power supply voltage: 3 Vdc
TAPE SPEED switch: 2.4 cm
Torque Measurement
Mode Torque Meter Meter Reading
0.49 – 1.27 mN • m
Forward CQ-103M (5 – 13 g • cm)
(0.07 – 0.180 oz • inch)
more than 2.95 mN • m
Fast Forward CQ-201M (more than 30 g • cm)
(more than 0.42 oz • inch)
more than 2.95 mN • m
Rewind CQ-201M (more than 30 g • cm)
(more than 0.42 oz • inch)
TapeTension Measurement
Mode Tension Meter Meter Reading
more than 20 g
Forward CQ-403M (more than 0.28 oz)
Record/Playback/Erase Head Azimuth Adjustment
Setting:
[VOL] control : mechanical mid
[TAPE SPEED] switch: 2.4 cm/s
[VOR] switch : OFF
Procedure:
1. Mode: Playback
Adjustment Location:
Specified voltage: 3 V (DC)
TestTape
Type Signal Used for Tape Speed
(cm/s)
S-2-A030 3 kHz, – 20 dB Head Azimuth Adjustment 2.4
WS-24 2.4
WS-12 3 kHz, – 10 dB TapeSpeedAdjustment 1.2
2. Turn the head azimuth adjustment screw to obtain the
maximum reading on level meter.
Note: Several peaks may appear, but the maximum.
First remove the cover (AZ).
Remove the
cover (AZ).
head azimuth
adjustment screw
+
–
level mete
r
test tape
S-2-A030
(3 kHz, –20 dB)
set
[EAR] jack (J101)
16
Ω

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M-640V/645V/647V
Specified Value:
Tape Speed Frequency counter
2.4 cm/s 2,880 to 3,120 Hz
1.2 cm/s 2,850 to 3,150 Hz
Tape Speed Adjustment
Setting:
[VOL] control: mechanical mid
[VOR] switch: OFF
Procedure:
Note: Reform 1.2 cm/s speed adjustment before 2.4 cm/s speed.
Adjustment mode: Playback
–
+
frequency counte
r
test tape
WS-24: tape speed 2.4cm/s
WS-12: tape speed 1.2cm/s
(3 kHz, –10 dB)
set
[EAR] jack (J101)
16
Ω
3. Check frequency difference between the beginning and the
end of the tape should be within ±0.5%.
2.4 cm/s: 15 Hz
1.2 cm/s: 15 Hz
Adjustment Location:
First remove the plate, blind.
1. Tape Speed: 2.4 cm/s
Playback WS-24 (tape center part) and adjust RV601 so that
reading on the frequency counter becomes 3,000 Hz.
2. Tape Speed: 1.2 cm/s
Playback WS-12 (tape center part) and adjust RV602 so that
reading on the frequency counter becomes 3,000 Hz.
Remove th
e
plate, blind.
RV601
2.4 cm/s
RV602
1.2 cm/s
tape speed adjustable resistors

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M-640V/645V/647V
MEMO