Sony Walkman WM-FX277 User manual

Ref. No. Part No. Description Remark
WM-FX241
SERVICE MANUAL
RADIO CASSETTE PLAYER
E Model
The WM-FX241(E Model) is approximately the same as the WM-FX277(5E Model).
Consequently, only difference between WM-FX241(E Model) and WM-FX277
(5E Model) are listed.
For other information, please refer to the WM-FX277 service manual (9-927-695-
31) previously issued.
1 3-227-307-11 CABINET(FRONT)
2 3-227-308-11 WINDOW(LCD)
14 3-227-306-11 CABINET(CENTER)
16 3-227-313-11 LID, BATTERY CASE
zDIFFERENCE PARTS LIST
EXPLODED VIEWS (Service Manual See page 17)
Ref. No. Part No. Description Remark Part No. Description Remark
3-227-307-01 CABINET(FRONT)
3-227-308-01 WINDOW(LCD)
3-227-306-01 CABINET(CENTER)
3-227-313-01 LID, BATTERY CASE
WM-FX277 (5E Model) WM-FX241 (E Model)
z ACCESSORIES & PACKING MATERIALS
3-225-744-11 MANUAL, INSTRUCTION (ENGLISH, SPANISH,
PORTUGUESE)
3-229-494-01 CASE, CARRYING
8-953-130-90 HEADPHONE MDR-E805LP
9-873-104-11
2001C0200-1
© 2001.3
Sony Corporation
Audio Entertainment Group
General Engineering Dept.
Ver 1.0 2001. 03

WM-FX241
REVISION HISTORY
Clicking the version allows you to jump to the revised page.
Also, clicking the version at the upper right on the revised page allows you to jump to the next revised
page.
Ver. Date Description of Revision
1.0 2001.03 New

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

1111
WM-FX277
5-2. BLOCK DIAGRAMS
• Abbreviation
MX : Mexican
CH : Chinese
E : Indication of country of origin (ST/FM MONO)
9E : No Indication of country of origin
5E, 6E : Indication of country of origin (DX/LOCAL)
TW : Taiwan
• Signal path.
F: FM
f: AM
E: PB
LCH
RCH
VREF
VREF
REV IN(L)
REV IN(R)
FWD IN(R)
FWD IN(L)
AVLS
NORM
LIMIT VOLUME
POWER IN(L)
MIX OUT(L)
R-CH
W
V
U
CAPSTAN/REEL
MOTOR
COM
W OUT
V OUT
U OUT
TAPE
SPEED
DRY BATTERY
SIZE "AA"
2PCS, 3V
32-44 45-48
S1-13 COM1-4
LIQUID CRYSTAL
ND701
SYSTEM
CONTROL
X IN
X OUT
R-CH IS OMITTED:SAME AS L-CH
3-6 7-9
PA0-3 PB1-3
DC-DC
CONVERTER
Q401
LOCAL
DX
FRONT-END,
IF,DET,FM MPX
CrO2/METAL
S303-2
HOLD
FM IN
AM IN
LPF OUT
LPF IN
E.O
SD
BAND
MEGA BASS
MUTE
PRE CTL
MOTOR CTL
BEEP
TAPE
RESET
RADIO ON
BATT REF
BATT CHECK
AMP ON
ID
VREF
S/S
PRE OUT(L)
PRE NF(L)
VSP
IN+
M VREF
L.B SW
MIX IN(L)
H.PIN(L)
SYSTEM
POWER OUT(L)
POWER OUT(COM)
POWER MUTE
OUT
MOTOR CONTROL
REF VOLTAGE
FOR SPEED CONTROL
CURRENT
DETECT
WAVE-
FORME
DETECT
SOFT
SWITCH
PRE
DRIVER
BIAS
R-CH
R-CH
HEAD
PLAYBACK
HP601
IC301
NORM
AM
IN
FM
RF
FM
OSC
AM
OSC
L-0
R-0
TUN
LED
FM
IF
AM
IF
FM
IN
FM/AM
MIX
LPF2
LPF1
IN
OUT
MPX
DET
AM
AM
AM
QUAD
AM
ANTENNA
L1
RF
FM
L2
FM
L3
OSC
OSC
+
L4
AM
BATT
BATT
IC702
BATT
IC1
R-CH
FM MONO
STEREO
(ON)
(OFF)
HOLD
FM/AM
PB AMP,
POWER AMP
(IEC DESIGNATION LR6)
S710-712
S708,709
S705,706
S702,703
KEY MATRIX
DISPLAY
FERRITE CORE SYSTEM
CONTROL
LOW BOOST
MIX
AMP AMP
POWER
VREF
COM
VCC
EQ
SWITCH
Q301
FM
FRONT-END
FM
OSC
FRONT-END
OSC
FM MPX
DET
DET
TU +2.6V
TU +2.6V
BPF
TU +2.6V
TU +2.6V
TU +2.6V
SWITCH
Q701
REG
Q501,502
TU +2.6V
VCC
INITIAL
RESET
+1.5V REG
IC701
OSC AMP
Q1,2
FM
TRACKING
AM
FREQUENCY
COVERAGE
TRACKING
AM
FREQUENCY
COVERAGE
FM
L1,CT1
L2
L3
L4
TU +2.6V
LPF1
5E,6E,MX
5E,6E,MX
E,9E,TW,CH
E,9E,TW,CH
E,9E,TW,CH

1212
WM-FX277
1
1
5
10
16
1 51012
13
15
24
20
25
30
35
36
37
40
48
45
17 20 25 30
32
33
35
40
45
48
49
50
55
60
64
213
S301
(TAPE ON)
1-680-658- 12
(12)
BE C
BE C
MAIN BOARD (SIDE A)
BE C
X701
5E,6E,MX
E,9E,TW,CH
Q701
R702
R501
R504
R503
R502
Q501
C501
C702
C704
C705
C707
C708
C709
C710
C711
R718
R720
R717
R605
R606
R607
R304
R710
R106
R206
C703
R711
R712
R713 R714 R715
R716
IC701
C701
R704
R705
R706
R707
C309
R303
C106
C206
R708
C603
R201
R202
R203
R101
R102
R103
R104
R601
R603
C101
C201
C302
C304
C105
C205
C604
C605
C606
C607
R604
C306
C108
C208
CT1
C301
R301
R6
C5
C6
C7
TH601
IC702
IC301
R302
R204
R722
C714
R703
IC1
R721
C716
C203
C103
C602
C601
R602
C715
C307
R726
R724
C314
D2
1
5
10
12
13
15
20
24
R15
R16
C25
C26
R5
R17
C13
R23
C42
C41
R10
C12
L702
L5 L401
L6
R21 R22
C23
C24
C43
Q301
Q502
C46
Q2
A
B
C
D
E
F
23 4 5 6 7 89 10
5-3. PRINTED WIRING BOARDS – MAIN SECTION (SIDE A) –
Note:
•X: parts extracted from the component side.
•a: Through hole.
•: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
• Abbreviation
MX : Mexican
CH : Chinese
E : Indication of country of origin (ST/FM MONO)
9E : No Indication of country of origin
5E, 6E : Indication of country of origin (DX/LOCAL)
TW : Taiwan
Ref. No. Location
zSemiconductor
Location
D2 C-7
IC1 C-8
IC301 E-4
IC701 E-6
IC702 D-5
Q2 C-6
Q301 F-5
Q501 C-3
Q502 B-3
Q701 B-4

1313
WM-FX277
5-4. PRINTED WIRING BOARDS – MAIN SECTION (SIDE B) –
2
J301
i
S303
-2 -1
S303
-2 -1
5E,6E,MX E,9E,TW,CH
5E,6E,MX E,9E,TW,CH
E,9E,TW,CH
CrO2/METAL
NORM
LOCAL
DX
-1
FM
MONO
ST
AVLS
S304 S304
-2 -1
LIMIT
NORM
MEGABASS
S709
S708
ENTER
LIQUID CRYSTAL
DISPLAY PANEL
BCE
PRESET
+
S705
TUNING–
S702
TUNING+
S703
L-CH
R-CH
HP601
PLAYBACK HEAD
PRESET
–
S706
S701
HOLD
ON
OFF
ORG
BLK
WHT
RED
WVU
COM M
M601
CAPSTAN/REEL
MOTOR
S712
OFF
S710
FM
S711
AM
L1
AM
FERRITE-BAR
ANTENNA 12
(12)
1-680-658-
MAIN BOARD (SIDE B)
HEAD FLEXIBLE BOARD
DRY BATTERY
SIZE "AA"
(IEC DESIGNATION R6)
2PCS, 3V
R205
R105
C107
C207
D1
D703
Q401
C311
R207
C209
C109
C40
IN
E
OUT
C2
R1
R2
C34
C35
C36
C3
D3
R8
R7
R13
C10
C9
C8
C29
C30
C17
C20
C18
C19
R12
R9
C27
R14
R11
C21
C4
R4
C14
C16
R18
C39
R3
R401
C401
R402
C403
C404
R403
R404
C44
C45
JR2
JR4
JR5
R107
R20
FB101
FB201
FB301
D401
C405
C406
C407
RV601
Q1
C712
VDD
C503
X701
T401
C303
C308
C305
C502
C104
C204
T1
C22
CF1
CF2
CP1
L2
L3
C402
C28
X2
L4
RV301
VOLUME
w
RV301
LCD701
G
D
E
F
A
B
C
13 4 5 6 7 89 10 11
Note:
•X: parts extracted from the component side.
•a: Through hole.
•f: internal component.
•: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
• Abbreviation
MX : Mexican
CH : Chinese
E : Indication of country of origin (ST/FM MONO)
9E : No Indication of country of origin
5E, 6E : Indication of country of origin (DX/LOCAL)
TW : Taiwan
Ref. No. Location
zSemiconductor
Location
D1 E-2
D3 B-3
D401 B-5
D703 B-10
Q1 D-3
Q401 B-5

1414
WM-FX277
5-5. SCHEMATIC DIAGRAM zRefer to page 15 for Notes. z Refer to page 15 for Waveforms. z Refer to page 16 for IC Block Diagrams.
COM
RI
S/S
PRE GND
PRE OUT(L)
PRE NF(L)
PRE OUT(R)
PRE NF(R)
FWDIN(L)
REVIN(L)
FWDIN(R)
REVIN(R)
VSP
IN+
MVREF
M GND
L.B SW
DET OUT
MIX IN(L)
H.PIN(L)
MIX IN(R)
H.PIN(R)
L.P2
VREF
R.REF
SYSTEM
POWER OUT(L)
POWER GND
POWER OUT(COM)
VCC
POWER OUT(R)
POWER MUTE
POWER IN(L)
POWER IN(R)
M VCC
OSC
UB
VB
WB
DR
MPGND
FC
OUT
MIX
OUT(L)
MIX
OUT(R)
W OUT
V OUT
U OUT
LIQUID CRYSTAL
N/R SW
BACK UP
AMP ON
BEEP
BATT CHECK
BATT REF
VSS
RADIO ON
MEGA BASS
MUTE
TAPE
PRE CTL
MOTOR CTL
ID
S13
TEST 1
LPF GND
LPF OUT
LPF IN
E.O
VSS
FM IN
VDD
TU VCC
RESET
DBR1
DBR2
DBR3
DBR4
SD
BAND
HOLD
PB2
PB3
PA0
PA1
PA2
TEST2
S12
S11
S10
S9
S8
S7
S6
S5
S4
S3
S2
S1
COM4
COM3
COM2
COM1
PB1
PA3
X OUT
X IN
LOCAL DX
NORM CrO2/METAL
- +
ENTER AM
FM
PRESET- PRESET+
MEGA BASS
TUNING
OFF
RCH
LCH
HEAD
PLAYBACK
-1
-2
AVLS
NORM
LIMIT
DRY BATTERY
SIZE "AA"
2PCS, 3V
(IEC DESIGNATION R6)
W
V
U
CAPSTAN/REEL
MOTOR
VOLUME
-1
-2
(LB8115W-NB-TLM)
AM
ANTENNA
AM
IN FM
RF FM
OSC AM
OSC
L-0
R-0
QUAD
ST
LED
TUN
LED
GND
FM
IF
AM
IF
AGC
GND
FM
IN
VCC1
VCC2
LPF3
FM/AM
MIX
LPF2
LPF1
IN
OUT MPX
DET
AFC
COM
L1
SYSTEM
CONTROL
FM/AM
DET,FM MPX
FRONT-END,IF AMP,
AM IN
+1.5V REG
MOTOR CONTROL
PB AMP,
POWER AMP
TAPE
SPEED
DISPLAY
LCD701
HOLD
ON
OFF
HP601
ST FM MONO
FERRITE BAR
OSC AMP
FM
TRACKING
L2
TRACKING
AM
L1,CT1
FREQUENCY
COVERAGE
FM
L3
AM
FREQUENCY
COVERAGE
L4
5E,6E,MX
AM IF
5E,6E,MX
5E,6E,MX
5E,6E,MX
*R18
4.7k
15k
5E,6E,MX
*C25,26
0.022
0.015
:5E,6E,MX
E,9E,TW,CH
E,9E,TW,CH
E,9E,TW,CH
E,9E,TW,CH
E,9E,TW,CH
E,9E,TW,CH
:E,9E,TW,CH

15
WM-FX277
Note on Schematic Diagram: MAIN SECTION
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ωand 1/4W or less unless otherwise
specified.
•f: internal component.
•C: panel designation.
•: B+ Line.
•H: adjustment for repair.
• Power voltage is dc 3V and fed with regulated dc power
supply from battery terminal.
• Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
• no mark : FM
():AM
< > : PLAY(TAPE)
• Voltages are taken with a VOM (Input impedance 10 MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
• Signal path.
F: FM
f: AM
E: PB
• Abbreviation
MX : Mexican
CH : Chinese
E : Indication of country of origin (ST/FM MONO)
9E : No Indication of country of origin
5E, 6E : Indication of country of origin (DX/LOCAL)
TW : Taiwan
zWaveforms
1
IC702 1
2
VOLT/DIV : 500 mV AC
TIME/DIV : 5 µsec
Q401 C
XOUT
1.5 Vp-p
13.3 µ sec
VOLT/DIV : 500 mV AC
TIME/DIV : 200 nsec
1.6 Vp-p
310 nsec

16
WM-FX277
AM RF IN FM RF OUT
FM RF IN
RF GND
AM LOW-CUT
FM/AM
MIX OUT
AGC
VCC
AM IF IN
FM IF IN
GND
TUN LED
ST LED
QUAD
FM OSC AM OSC AFC DET OUT MPX IN LPF2 LPF1 L-OUT R-OUT
7
5431 2 6 8 9 1210 11
141516
17
181921 20 24 23
RF VCC
22 13
ΦΦ DECODER
VCO
DIVIDER
ST/MONO
FM/AM
AF
AMP
FM
MUTE
AF BUFFER
FM
DET
AM
DET
AM
RF AMP
FM
RF AMP
FM
MIX
FM
OSC
AM
OSC
AM
MIX
TUN
LED
ST
LED
FM IF
AMP
AM IF
AMP
AGC
LEVEL
DET
• IC BLOCK DIAGRAMS
IC1 TA2111F-(EL)
IC301 LB8115W-NA-TLM
1
236
35
34
33
32
31
30
29
28
27
26
25
13 14 15 16 17 18 19 20 21 22 23 24
48 47 46 45 44 43 42 41 40 39 38 37
COM
RI
VREF
POWER OUT (COM)
POWER OUT (R)
VCC
POWER MUTE
POWER IN (L)
POWER IN (R)
MIX OUT (L)
MIX OUT (R)
LP.2
H.P IN (R)
H.P IN (L)
DET OUT
MVREF
IN
+
VSP
MIX IN (R)
MIX IN (L)
LOW BOOST SW
M-GND
R.REF
SYSTEM
POWER OUT (L)
POWER GND
MVCC DR WOUT MP-GND VOUT UOUT FC OUT OSC UB VB WB
3
4
5
6
7
8
9
10
11
12
PRE NF (L)
PRE OUT (R)
PRE NF (R)
PRE FWD IN (R)
PRE REV IN (R)
PRE REV IN (L)
PRE FWD IN (L)
S/S
PRE GND
PRE OUT (L)
BIAS
R.F
REF SYS
CONT
DET
VREF
SPEED
LOW
BOOST
PRE DRIVER
OPERATION LOGIC
OSC
PLUSE DET
REF
VOLTAGE
REF VOLTAGE
FOR SPEED CONTROL
CURRENT
DET
OPERATION
DET
FWD/
REV
FREQ
CARC.
+
—

WM-FX277
17
SECTION 6
EXPLODED VIEWS
NOTE :
• -XX, -X mean standardized parts, so they
may have some difference from the original
one.
• Items marked “ * ”are not stocked since they
are seldom required for routine service. Some
delay should be anticipated when ordering
these items.
• The mechanical parts with no reference
number in the exploded views are not
supplied.
• Hardware (# mark) list and accessories and packing
materials are given in the last of this parts list.
• Abbreviation
MX :Mexican
CH :Chinese
E :Indication of country of origin (ST/FM MONO)
9E :No Indication of country of origin
5E, 6E :Indication of country of origin (DX/LOCAL)
TW :Taiwan
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
6-1. CABINET SECTION
L1
LCD701
1
2
3
45
6
7
8
9
10
11
12
13 14
15
16
17
18
19
20
1 3-227-307-11 CABINET (FRONT)
2 3-227-308-11 WINDOW (LCD)
3 3-227-309-01 KNOB (HOLD)
4 3-227-310-01 BUTTON (PRESET)
5 3-015-285-01 SCREW (M1.4),TOOTHED LOCK (WH)
* 6 A-3021-397-A MAIN PC BOARD ASSY (5E,6E,MX)
* 6 A-3021-398-A MAIN PC BOARD ASSY (E,9E,TW,CH)
7 3-227-312-01 STOPPER
8 3-227-317-01 BUTTON (STOP)
9 3-227-315-01 BUTTON (FF)
10 3-227-314-01 BUTTON (PLAY)
11 3-227-316-01 BUTTON (REW)
12 3-227-305-11 CASSETTE, HOLDER
13 3-007-012-01 SPRING (TORSION)
14 3-227-306-11 CABINET (CENTER) (5E,6E,MX)
14 3-227-306-21 CABINET (CENTER) (E,9E,TW,CH)
15 3-227-741-01 SPRING (CASSETTE)
16 3-227-313-11 LID, BATTERY CASE
17 3-229-320-01 TERMINAL (+), BATTERY
18 3-229-321-01 TERMINAL (-), BATTERY
19 3-229-658-01 PLATE, CONNECTION CONDUCTIVE
20 3-227-311-01 HOLDER (LCD)
L1 1-754-176-11 COIL, FERRITE-ROD ANTENNA (MW)
LCD701 1-804-311-11 DISPLAY PANEL, LIQUID CRYSTAL

18
WM-FX277
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
6-2. MECHANISM DECK SECTION
(MF-WMFX241-114)
HP601
M601
not
supplied
51
53
54
55
55
56
56
58 59
68
61
62
63
64
65
66
67
57
69
60
not
supplied
not
supplied
not supplied
not
supplied
not
supplied
not
supplied
not
supplied
51 X-3369-749-1 PINCH LEVER (N) ASSY
53 X-3372-619-1 WHEEL ASSY (SP), CAPSTAN
54 3-703-816-73 SCREW (M1.4), SPECIAL HEAD
55 3-019-776-01 GEAR (REEL-S)
56 3-921-797-01 WASHER
57 3-036-664-01 SPRING (FR LEVER OWN)
58 3-013-560-11 BELT
59 3-022-094-01 SPRING (STOP-S)
60 3-022-093-01 SPRING (FR-S)
61 X-3374-598-1 CLUTCH ASSY (S)
62 3-920-990-01 SPRING (UD), COMPRESSION
63 3-921-335-01 WASHER, LEVER
64 3-019-778-01 SLEEVE (MS)
65 3-728-091-01 WASHER, STOPPER
66 3-019-777-01 LEVER (OWS), DETECTION
67 3-704-197-01 SCREW (M1.4), SPECIAL HEAD
68 3-025-454-01 SPRING (SW-S)
*69 X-3374-601-1 CHASSIS ASSY (GL-OS)
HP601 1-500-641-11 HEAD, MAGNETIC (PLAYBACK)
M601 1-763-468-13 MOTOR, DC (CAPSTAN/REEL)
(INCLUDING PULLEY)