Sony Walkman WM-FX277 User manual

Ver 1.0 2001.03
WM-FX277
SERVICE MANUAL
RADIO CASSETTE PLAYER
SPECIFICATIONS
E Model
Chinese Model
Model Name Using Similar Mechanism NEW
MD Mechanism Type MF-WMFX241-114
9-927-695-31
2001C0200-1
© 2001.3
Sony Corporation
Audio Entertainment Group
General Engineering Dept.

2
WM-FX277
Specifications ........................................................................... 1
1. SERVICING NOTE ...................................................... 3
2. GENERAL ...................................................................... 3
3. DISASSEMBLY
3-1. Cabinet (Front) ........................................................... 4
3-2. Main Board ................................................................. 4
3-3. Mechanism Deck ........................................................ 5
3-4. Belt, Capstan/reel Motor (M601),
Magnetic Head (Playback) (HP601) ........................... 5
3-5. Cassette Holder ........................................................... 6
4. ADJUSTMENTS
4-1. Mechanical Adjustments ............................................ 7
4-2. Electrical Adjustments ................................................ 7
5. DIAGRAMS
5-1. Explanation of IC Terminals ..................................... 10
5-2. Block Diagram ........................................................... 11
5-3. Printed Wiring Boards – Main Section (Side A) – ... 12
5-4. Printed Wiring Boards – Main Section (Side B) – ... 13
5-5. Schematic Diagram ................................................... 14
6. EXPLODED VIEWS
6-1. Cabinet Section ......................................................... 17
6-2. Mechanism Deck Section (MF-WMFX241-114) ..... 18
7. ELECTRICAL PARTS LIST ................................... 19
Flexible Circuit Board Repairing
• Keep the temperature of the 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.
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.
TABLE OF CONTENTS

3
WM-FX277
SECTION 1
SERVICING NOTE
In case of adjusting Tape Speed, you can easily to adjust RV601 by removing 7 claws on Window (LCD) and itself as shown in the figure.
1.Insert the precision screwdriver (Cover a point by cloth) in to the slit at claw.
2.Remove the window(LCD).
Note: Be careful not to damage claws.
Claws
Window(LCD)
Claws
Claws
RV601
SECTION 2
GENERAL This section is extracted from
instruction manual.
LOCATION AND FUNCTION OF CONTROLS

4
WM-FX277 SECTION 3
DISASSEMBLY
Note : Follow the disassembly procedure in the numerical order given.
3-1. CASSETT HOLDER ASSY, CABINET (FRONT)
3-2. MAIN BOARD
• The equipment can be removed using the following procedure.
Main boardCassette holder ASSY
Cabinet (Front) Cassette holder
Mechanism deck Belt, Capstan/reel motor (M601),
Magnetic head (Playback) (HP601)
Set
Cabinet (Front)
Cassette holder ASS
Y
4 Claws
4 Claw
2
5
1 Claws
1 Claws
3 Claws
1 Claws
Main board
1 Screw
Orange
Black
White
Red
Cassette holder ASS
Y
Head flexible board
2 Remove solder
3 Claws
4
Note : Use the precision driver with coverd a point
by cloth to release the claw.
Be careful not to damage claws.

5
WM-FX277
3-3. MECHANISM DECK
3-4. BELT, CAPSTAN/REEL MOTOR (M601), MAGNETIC HEAD (PLAYBACK)(HP601)
Mechanism deck
Cassette holder ASS
Y
1 Claws
2
2 Belt
Stopper
1 Claw
6 magnetic head
(PLAYBACK)
(HP601)
4 Capstan/reel motor
(M601)
3 Screws (M1.4)
5 Screws (M1.4)
Mechanism dec
k

6
WM-FX277
1Insert the spring (torsion) to the L shape slot as shown in the figure.
2,3Insert the hinge of the “Cassette holder ”.
4Close the “Cassette holder”then press it.
3-5. CASSETTE HOLDER
zCAUTIONS DURING ASSEMBLY
Cassette holder
4 Spring (torsion)
Hinge
Hinge
Projection
1
5
Hinge
Cabinet (center)
Hinge
Projection
Projection
Projection
3 Move the hinge away
from projection
2 Move the hinge away
from projection
Spring (torsion)
L shape slot
Hinge
Hinge
Cassette holde
r
Cabinet (center)
124
3

7
WM-FX277
4-1. MECHANICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab :
playback head pinch roller
capstan rubber belt
2. Demagnetize the playback head with a head demagnetizer.
Do not use a magnetized screwdriver for the adjustments.
3. These measurement and adjustment should be performed with
the rated power supply voltage (2.5 V) unless otherwise noted.
Torque Measurement
Mode Torque meter Meter reading
FWD
1.97 to 4.90 mN•m
20 to 50 g • cm
CQ-102C (0.28 to 0.69 oz• inch)
FWD
less than 0.19 mN•m
less than 2 g • cm
back tension (less than 0.027 oz• inch)
FF, REW CQ-201B
5.89 to 19.61 mN•m
60 to 200 g • cm
(0.84 to 2.77 oz• inch)
SECTION 4
ADJUSTMENTS
4-2. ELECTRICAL ADJUSTMENTS
PRECAUTION
• Supplied voltage : 2.5V.
• Switch and control position
MEGA BASS (S709) : OFF
VOLUME control (RV301) : maximum
AVLS (S304) : NORM
TAPE SECTION
Test Tape
Type Signal Used for
WS-48A 3kHz, 0dB Tape Speed Adjustment
Tape Speed Adjustment
Procedure :
1. Playback WS-48A (tape center part) and adjust RV601 so that
the frequency counter reading becomes 3,000Hz.
Standard value : 2,985–3,015Hz
2. Playback WS-48A (tape top and end) .
Check that frequency counter reading is within ±1.0% of the
reading of step 1.
Adjustment Location :
0 dB = 0.775V
set
test tape
WS-48A
(3kHz, 0dB)
frequency counte
r
16 Ω
phones jack (J301)
RV601:
Tape speed Adjustmen
t
Refer to page 3 for Servicing note

8
WM-FX277
TUNER SECTION
AM section
BAND : AM
FM section
BAND :FM
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1 1400kHz <1395kHz>
AM FREQUENCY COVERAGE ADJUSTMENT
Adjust parts Frequency display Reading on digtal
voltmeter
L4 530kHz <531kHz>Adjustment value : 1.2V
Standard value : 1.1–1.3V
Confirmation 1,710kHz <1,602kHz>Standard value : 9V or less
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L1 620kHz <621kHz>
CT1 1,400kHz <1,395kHz>
FM FREQUENCY COVERAGE ADJUSTMENT
Frequency display Reading on digtal voltmeter
L3 108MHz Adjustment value : 9.0V
Standard value : 8.7–9.3V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L2 98MHz
Confirmation 108MHz
Adjustment Location : Main board
0 dB = 1µV• Repeat the procedures in each adjustment several times, and the
frequency coverage and tracking adjustments should be finally
done by the trimmer capacitors.
AM RF signal
generator
30% amplitude modulation by 400Hz
signal.
Output level : as low as possible
Put the lead-wire
antenna close to
the set.
set
16
Ω
phones jack (J301)
level meter
Frequency Coverage Adjustment
Setting :
S303
-2 -1
R207
C10
9
C40
IN
E
OUT
C29
C30 R
9
C1
6
JR2
JR4
JR5
R107
FB101
CF2
CP1
FM RF signal
generator
33.75kHz frequency deviation
by 1kHz signal.
Output level :
as low as possible
CP1 IN
0.01
µ F
[MAIN BOARD]
(Side B)
C403
R403
TP
(VT)
GND
R404
C405
C303
C402
TP (VT)
TP (GND)
[MAIN BOARD]
(Side B)
digital voltmeter
(DC range)
no mark : 10kHz step
< > : 9kHz step

9
WM-FX277
Adjustment Location :
[MAIN BOARD] (SIDE A)
L3 : FM Frequency Coverage Adjustment
L2 : FM tracking Adjustment
L4 : AM Frequency Coverage Adjustment
T1 : AM IF Adjustment
CT1 : AM Tracking Adjustment
L1 : AM Tracking Adjustment
IC1

10
WM-FX277 SECTION 5
DIAGRAMS
Pin No. Pin name I/O Descliption
1 XOUT O Crystal oscillator output (75kHz).
2 TEST2 – Not used (Ground).
3 PA3 I Key input.
4 PA2 I Key input.
5 PA1 I Key input.
6 PA0 I Key input.
7 PB3 O Key output.
8 PB2 O Key output.
9 PB1 O Key output.
10 LOCAL/DX – Not used (OPEN).
11 HOLD I HOLD switch input. “H”: ON, “L”: OFF
12 LOCAL SW – Not used (OPEN).
13 TV (H) – Not used (OPEN).
14 BAND O Band select signal output.
15 SD I Tuning signal detect input.
16 COMP – Not used (OPEN)
17 N/R SW – Not used (OPEN)
18 BACK UP I Back up voltage input.
19 AMP ON O Power ON/OFF signal output.
20 BEEP O Beep signal output.
21 BATT CHECK I Back up cancel input.
22 BATT REF I A/D reference voltage input.
23 –––––––––– – Not used (Ground).
24 VSS – Ground terminal.
25 RADIO ON O Radio ON signal output.
26 MEGA BASS O MEGA BASS ON signal output.
27 MUTE O Mute ON signal output.
28 TAPE I Tape ON input.
29 PRE CTL O Preamplifier control output.
30 MOTOR CTL O Motor control output.
31 ID I Destination select input.
32-44 S1-13 O LCD segment output.
45-48 COM1-4 O LCD common output.
49-52 DBR1-4 – LCD power supply.
53 RESET I Reset input (Fixed “H”).
54 TU VCC – Not used (OPEN).
55 VDD – Power supply.
56 FM IN I FM osc frequency input.
57 AM IN I AM osc frequency input.
58 VSS – Ground terminal.
59 E.O O Error (PWM) signal output.
60 LPF IN I LPF input.
61 LPF OUT O LPF output.
62 LPF GND – Ground terminal.
63 TEST 1 – Not used (Ground).
64 X IN I Crystal oscillator input (75kHz).
5-1. EXPLANATION OF IC TERMINALS
IC702 LC72348W-9A36 SYSTEM CONTROL