Sony Walkman WM-FX477 User manual

– 1 –
MICROFILM
SERVICE MANUAL
US Model
Canadian Model
AEP Model
E Model
Chinese Model
WM-FX477/FX479
RADIO CASSETTE PLAYER
Photo: WM-FX477
Radio section
Frequency range
FM: 65 – 74/87.5 – 108 MHz (East
European)
87.5 – 108 MHz (Except East European)
AM:530 – 1,710 kHz (US, Canadian)
531 – 1,602 kHz (Except US, Canadian)
Tape section
Frequency response
(Dolby NR off)
Playback: 30 – 14,000 Hz
Output
Headphones/earphones (2jack)
Load impedance 8 – 300 ohms
General
Power requirements
3 V DC batteries R6 (AA) ×2/
External DC 3 V power sources
Dimensions (w/h/d)
Approx. 115.8 ×85 ×33.4 mm
(4 5/8 ×3 3/8 ×1 3/8 inches) incl.
projecting parts and controls
Mass
Approx. 175 g (6.2 oz.)/Approx.
255 g (9.0 oz.) incl.batteries and a
cassette
Supplied accessories
Stereo headphones or Stereo
earphones (1)
Carrying case (1)
Design and specifications are subject to change without
notice.
SPECIFICATIONS
Model Name Using Similar Mechanism WM-FX483
Tape Transport Mechanism Type MF-WMFX483-147
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.
DolbynoisereductionmanufacturedunderlicensefromDolbyLabo-
ratories Licensing Corporation.
“DOLBY” and the double-D symbol aare trademarks of Dolby
Laboratories Licensing Corporation.
Ver 1.0 1999. 02

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TABLE OF CONTENTS
1. GENERAL ........................................................................... 3
2. DISASSEMBLY
2-1. Cabinet (Front) Assy ........................................................... 5
2-2. Display Board ..................................................................... 6
2-3. Holder (Sub) Assy, Cassette ................................................ 6
2-4. Main Board ......................................................................... 7
2-5. Mechanism Deck................................................................. 7
2-6. Belt and Motor .................................................................... 8
3. MECHANICAL ADJUSTMENTS ................................. 9
4. ELECTRICAL ADJUSTMENTS
Tape Section ............................................................................ 9
Tuner Section......................................................................... 10
5. DIAGRAMS
5-1. IC Pin Description............................................................. 12
5-2. Block Diagram .................................................................. 14
5-3. Schematic Diagram –Main Section–................................. 16
5-4. Printed Wiring Board –Main Section– .............................. 19
5-5. Printed Wiring Board –Display Section– .......................... 21
5-6. Schematic Diagram –Display Section–............................. 23
6. EXPLODED VIEWS
6-1. Cabinet Section ................................................................. 26
6-2. Tape Mechanism Deck Section ......................................... 28
7. ELECTRICAL PARTS LIST......................................... 29

– 3 –
SECTION 1
GENERAL This section is extracted
from instruction manual.

– 4 –

– 5 –
B
C
DEF
G
H
I
J
K
S701
cabinet (front) assy
A
cabinet (front) assy
2 screw (1.7x2.5), tapping
1 screw (1.7x2.5), tapping
holder (sub) assy, cassette
Cabinet (front) assySet Main board
Holder (sub) assy, cassette
Belt and MotorMechanism deckDisplay board
SECTION 2
DISASSEMBLY
2-1. CABINET (FRONT) ASSY
Note : When installing, fit the knobs and switches.
3 Insert the precision screwdriver
(1.4 mm flat-blade) into the slit
at claw A and release the claw.
4 Remove the cabinet (front) assy.
(Release all claws B to K in
alphabetical order.)
• The equipment can be removed using the following procedure.
Note : Follow the disassembly procedure in the numerical order given.
Note :When removing the cabinet, put cloth
on the end of a screwdriver or use a
polyacetal driver to avoid damage to
the cabinet.

– 6 –
1 Open the holder (sub) assy, cassette.
4 holder (sub) assy, cassette
A
B5
spring (torsion)
2 four claws
3 DISPLAY board
1 screws
2-2. DISPLAY BOARD
2-3. HOLDER (SUB) ASSY, CASSETTE
2 Insert a precision screwdriver
(1.4 mm flat-blade) vertically
into portion A to release the
hinge plate.
3 Portion B to release the
hinge plate.

– 7 –
5 three claws
4 three claws
1 HEAD FLEXIBLE board (CN303)
2 Unsolder the 4 places.
3 screw (M1.4x2.0), locking
6 MAIN board
switch
slider
2-5. MECHANISM DECK
2-4. MAIN BOARD
Note : When installing, fit the switch and slider.
2 Insert the precision screwdriver
(1.4 mm flat-blade) into the slit
and release three claws.
4 Remove the mechanism deck
in the direction of the arrow.
1 screw
3 three claws

– 8 –
1 belt
3 motor
wheel assy (SP), capstan
belt
• How to apply the belt
M901
2 two screws (screw (M1.4), special head)
2-6. BELT AND MOTOR

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RV601
0000
2 jack (J301)
digital frequency
counter
set
16
Ω
test tape
WS-48A
(3 kHz, 0 dB)
PRECAUTION
• Supplied voltage : 2.5V
• Control position
VOL control : maximum
• Test Tape
Type Signal Used for
WS-48A 3 kHz, 0 dB tape speed adjustment
TAPE SECTION 0 dB = 0.775 V
Tape Speed Adjustment
Procedure:
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
playback head pinch lever assy
capstan wheel assy rubber belt
2. Demagnetize the playback head with a head demagnetizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage (2.5V) unless otherwise noted.
Torque Measurement
Mode Torque meter Meter reading
FWD CQ-102C 20 – 42 g • cm
(0.28 – 0.58 oz • inch)
FWD CQ-102C less than 2 g • cm
Back Tension (less than 0.03 oz • inch)
REV CQ-102RC 20 – 42 g • cm
(0.28 – 0.58 oz • inch)
REV CQ-102RC less than 2 g • cm
Back Tension (less than 0.03 oz • inch)
FF, REW CQ-201B more than 60 g • cm
(more than 0.83 oz • inch)
SECTION 4
ELECTRICAL ADJUSTMENTS
SECTION 3
MECHANICAL ADJUSTMENTS
1. Playback WS-48A (tape center part) in the FWD state and
adjust RV601 so that the frequency counter reading
becomes 3,000 Hz.
Specification Value:
Digital frequency counter
2,985 to 3,015 Hz
2. Playback WS-48A (tape center part) in the REV state.
Check that the frequency counter reading is within ± 1.0% of
the reading of step 1.
Adjustment Location:

– 10 –
2 jack (J301)
set
16
Ω
level meter
(range: 0.5-5 V ac
)
Put the lead-wire
antenna close to
the set.
AM RF signal
generator
digital
voltmeter
TP (VT)
Main board
2 jack (J301)
set
16
Ω
level meter
(range: 0.5-5 V ac
)
FM RF signal
generator
0.01 µ F(FM RF IN)
Main boar
d
(GND)
digital
voltmeter
TP (VT)
Main board
• Repeat the procedures in each adjustment several times, and the
tracking adjustment should be finally done by the trimmer ca-
pacitors.
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1
1,000 (999) kHz
( ): Except US, Canadian model
AMTRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L2 CT1
620 (621) kHz 1,400 (1,395) kHz
( ): Except US, Canadian model
TUNER SECTION 0 dB = 1 µV
• FM Section
Setting:
RADIO ON/BAND switch : FM
FM Tuning Voltage Adjustment
FM TUNING VOLTAGE ADJUSTMENT
Adjust for a 9.0 (14.5 ± 0.5) Vdc reading on digital voltmeter.
L3
108 MHz
FM Tracking Adjustment
Modulation: 1 kHz, 75 kHz dev. (100%)
Output level: as low as possible
FMTRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L1
87.5 (65.0) MHz
( ): East European model
+0.5
0
• AM Section
Setting:
RADIO ON/BAND switch : AM
AM Tuning Voltage Adjustment
AMTUNING VOLTAGE ADJUSTMENT
Adjust for a 1.4 ± 0.1 Vdc reading on digital voltmeter.
L4
530 (531) kHz
( ): Except US, Canadian model
AM IF Adjustment, AMTracking Adjustment
Modulation: 400 Hz, 30%
Output level: as low as possible