Sony Walkman WM-GX221 User manual

WM-GX221
US Model
Canadian Model
E Model
Chinese Model
SERVICE MANUAL
RADIO CASSETTE-CORDER
Sony Corporation
Personal Audio Company
Published by Sony Engineering Corporation
9-873-412-03
2004D16-1
© 2004.04
SPECIFICATIONS
Ver 1.2 2004.04
Model Name Using Similar Mechanism New
Tape Transport Mechanism Type MT-WMGX221-175
Frequency range
FM: 87.5-108 MHz (Italy and Saudi Arabia)
87.6-108 MHz (North, Central and South America)
87.6-107.9 MHz (Other countries)
AM: 526.5-1 606.5 kHz (Italy and Saudi Arabia)
530-1 710 kHz (North, Central and South America)
531-1 602 kHz (Other countries)
Frequency response Playback: 40 - 15 000 Hz
Recording: 100 - 8 000 Hz (when
setting 2x REC TIME to NORM)
Input Microphone (MIC) jack
Output Headphones (i) jack
Load impedance 8 - 300 Ω
Power requirements 3 V DC batteries R6 (size AA) ×2
External DC 3V power sources
Dimensions (w/h/d) Approx. 112.0 ×82.5 ×38.0 mm
(4
1
/
2
×3
1
/
4
×1
1
/
2
inches), excl.
projecting parts and controls
Mass Approx. 190 g (6.8oz) (main unit
only)
Supplied accessories Stereo headphones or earphones (1)
Stereo microphone (1)
Carrying case (1)
Design and specifications are subject to change without notice.
Battery life (Approx. hours) (JEITA*)
Sony alkaline LR6(SG) ** Sony R6P(SR)
(using headphones/earphones)
playback 24 7
radio 48 15
mic recording 20 4.5
radio recording 12 3
(using the speakers)
playback 15 4.5
radio 26 6
radio recording 11.5 3
*Measured value by the standard of JEITA (Japan
Electronics and Information Technology Industries
Association) (using a Sony HF series cassette tape).
**When using Sony LR6(SG) “STAMINA” alkaline dry
batteries (produced in Japan).
Note
•The battery life may be shorter depending on the
operating condition, the surrounding temperature
and battery type.

2
TABLE OF CONTENTS
WM-GX221
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.
1. SERVICE NOTE ··············································································· 3
2. GENERAL ·························································································· 4
3. DISASSEMBLY ················································································ 5
3-1. Panel (Cabinet Front), Cabinet (Front) Assy ·································· 5
3-2. MAIN Board, Mechanism Deck (MT-WMGX221-175) ················ 6
3-3. HE901, HRP901, M601, Belts························································ 7
3-4. SUB Board ······················································································ 7
4. MECHANICAL ADJUSTMENT ·················································· 8
5. ELECTRICAL ADJUSTMENT······················································ 8
6. DIAGRAMS ······················································································ 10
6-1. Block Diagram – Tuner Section – ················································· 11
6-2. Block Diagram – Main Section – ················································· 12
6-3. Printed Wiring Boards ·································································· 13
6-4. Schematic Diagram – MAIN Board (1/2) –·································· 14
6-5. Schematic Diagram – MAIN Board (2/2) –·································· 15
6-6. IC Block Diagrams ······································································· 16
7. EXPLODED VIEWS ······································································ 17
7-1. Overall Section ············································································· 17
7-2. Cabinet (Front) Section ································································· 18
7-3. Mechanism Deck Block-1 (MT-WMGX221-175) ······················· 19
7-4. Mechanism Deck Block-2 (MT-WMGX221-175) ······················· 20
8. ELECTRICAL PARTS LIST ······················································· 21

3
WM-GX221
SECTION 1
SERVICE NOTE
In this set, record/play mode is detected using the switch S704 (TAPE POWER).
S704 is mounted on the MAIN board. If MAIN board is removed, it becomes impossible to detect
record/play mode.
Where MAIN board is removed, when you measure operation and voltage of each part of the mechanism
deck, please turn on S704.
– MAIN BOARD (SIDE A) —
S704

4
WM-GX221 SECTION 2
GENERAL This section is extracted
from instruction manual.
* There is a tactile dot beside VOL on the main unit to show the direction to turn up the
volume.
** The button/jack has a tactile dot.
PAUSE
z REC
FLUNCTION (TAPE/RADIO)
NORM/CrO2 /METAL•
FM ST/MONO
DX/LOCAL
ISS
Built-in microphone
DC IN 3V
SPEAKER/ i
i
x STOP
N PLAY**
VOL *
BAND (FM/AM)
SOUND BOOST
(OFF/ON)
TUNING
REC/BATT indicator
Tuning indicator
MIC (PLUG IN POWER)** 2x REC TIME
(NORM/DOUBLE)
AVLS (NORM/LIMIT)
m REW/REVIEW
M FF/CUE
•LOCATION OF CONTROLS

5
WM-GX221
SECTION 3
DISASSEMBLY
Note : Disassemble the unit in the order as shown below.
Note : Follow the disassembly procedure in the numerical order given.
3-1. PANEL (CABINET FRONT), CABINET (FRONT) ASSY
two screws (B1.7 × 1.4)
1
2
screw (B1.7 × 1.4)
1
two screws (B1.7 × 1.4
)
3
two screws
3
screw
3
screw (B1.7 × 1.4)
1
two screws (B1.7 × 9)
3
Remove solder.
(two places)
6
Remove solder.
(two places)
6
cabinet (front) assy
panel (cabinet front)
four claws
4
claw
4
two claws
4
flexible board
5
cabinet center
Panel (cabinet front), Cabinet (front) assy
MAIN board, Mechanism deck (MT-WMGX221-175)
HE901, HRP901, M601, Belts
SUB board
Set

6
WM-GX221
3-2. MAIN BOARD, MECHANISM DECK (MT-WMGX221-175)
two screws
6
MAIN board
9
two screws
5
joint cover
7
three screws (B1.7 × 9)
3
spring (torsion)
2
cassette holder sub assy
Remove solder
(four places)
8
MT-WMGX221-175
cabinet center
1
4
<Caution of the pointer attachment>
The pointer is slid, even a stopper is
brougth near, and CV1 is turned with
all its might clockwise, and is attached.

7
WM-GX221
3-3. HE901, HRP901, M601, BELTS
3-4. SUB BOARD
four screws (B1.7)
1
SUB board
2
cabinet (front) ass
y
panel (MIC)
two screws (M1.4)
2
M601
(capstan/reel
motor)
3
1
7
6
capstan fly assy (AR)
washer
5
washer
6
9
qa
8
washer
(stopper N)
two screws
HE901
(erase head)
0
screw
HRP901
(REC/PB head)
Attaching belt (CAP)
and belt (pulley).
belt (CAP)
belt (CAP)
z

8
WM-GX221 SECTION 4
MECHANICAL ADJUSTMENT
SECTION 5
ELECTRICAL ADJUSTMENT
PRECAUTION
1. Specified voltage: 2.5 V (DC)
2. Switch and control position
VOL : MAX
SPEAKER : OFF
AVLS : NORM
SOUND BOOST : OFF
PB EQ : NORM
PAUSE : OFF
ISS : 1
FM SENSE : DX
(US, 5E)
FM MODE : FM ST
(EXCEPT US, 5E)
2X REC TIME : NORM
• Abbreviation
5E : E model with the indication of the country of origin.
TAPE SECTION
Tape Speed Adjustment
Procedure:
1. Enter the FWD playback mode.
2. Adjust RV601 so that the value of the frequency counter reading
becomes 3,000 Hz.
Specification value:
Frequency counter
2,985 Hz – 3,015 Hz
3. Check that the frequency deviation at the beginning and ending
of a tape is within 1.5 % (45 Hz).
4. Set the 2x REC TIME switch to DOUBLE (2.4 cm/s).
5. Adjust RV602 so that the value of the frequency counter reading
becomes 1,500 Hz.
Adjustment Location : MAIN board (see page 9)
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 head with a head demagnet-
izer. (Do not bring a head demagnetizer close to the erase
head.)
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.
• Torque Measurement
Signal
3 kHz, 0 dB
Used for
Tape Speed Adjustment
Tape
WS-48A
Test tape
WS-48A
(3kHz, 0dB)
Set
2 jack (J301)
16
Ω (EXCEPT US MODEL)
32 Ω (US MODEL)
Frequency counte
r
+
–
Mode
FWD
FWD
Back Tension
REV
REV
Back Tension
FF, REW
Torque Meter
CQ-102C
CQ-102C
CQ-102RC
CQ-102RC
CQ-201B
Meter Reading
19.6 to 29.4 mN•m
(20 to 30 g•cm)
(0.28 to 0.42 oz•inch)
Less than 1.96 mN•m
(Less than 2.0g•cm)
(Less than 0.028 oz•inch)
19.6 to 29.4 mN•m
(20 to 30 g•cm)
(0.28 to 0.42 oz•inch)
Less than 1.96 mN•m
(Less than 2.0g•cm)
(Less than 0.028 oz•inch)
More than 39.2 mN•m
(More than 40 g•cm)
(More than 0.56 oz•inch)

9
WM-GX221
[AM]
BAND : AM
[FM]
BAND : FM
AM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter.
L4 505 kHz (516.5 kHz)
CT1-4 1,760 kHz [1,690 kHz] (1,631.5 kHz)
[ ] : E, 9E, CH, TW MODEL ( ) : EA MODEL
no mark : OTHER MODELS
TUNER SECTION
0.01 µ F
FM RF signal
generator
to ANT (FM IN)
75kHz frequency deviation by 1kHz signal.
Output level : as low as possible
Put the lead-wire
antenna close to
the set.
30% amplitude modulation by 400 Hz
signal.
Output level : as low as possible
AM RF signal
generator
set +
–
level mete
r
2 jack (J301)
16
Ω (EXCEPT US MODEL)
32
Ω (US MODEL)
0dB=1µV
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1 455 kHz
FM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter.
L3 86.0 MHz (87.35 MHz)
CT1-3 109.5 MHz (108.25 MHz)
( ) : EA MODEL
no mark : OTHER MODELS
•Repeat the procedures in each adjustment several times.
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L1 620 kHz
CT1-1 1,400 kHz
[MAIN BOARD] — SIDE B —
Adjustment Parts Location :
[MAIN BOARD] — SIDE A —
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L2 86.0 MHz (87.35 MHz)
CT1-2 109.5 MHz (108.25 MHz)
( ) : EA MODEL
no mark : OTHER MODELS
•Abbreviation
9E : E model without the indication of the country of origin.
CH : Chinese model
EA : Saudi Arabia model
TW: Taiwan model
CT1-3
CT1-4
CT1-2 CT1-1
RV602
RV601
L4
L3
L2 T1
L1
CT1-3 : FM frequency
coverage adjustment
CT1-4 : AM frequency
coverage adjustment
CT1-2 : FM tracking
adjustment
CT1-1 : AM tracking
adjustment
RV601 : Tape speed adjustment
(NORM)
RV602 : Tape speed adjustment
(DOUBLE)
L4 : AM frequency
coverage adjustment
L3 : FM frequency
coverage adjustment
L1 : AM tracking
adjustment
L2 : FM tracking
adjustment
T1 : AM IF
adjustment
Ver 1.1 2002.06

10
WM-GX221
SECTION 6
DIAGRAMS
• WAVEFORMS
Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. p: pF.
50 WV or less are not indicated except for electrolytics and
tantalums.
•All resistors are in Ωand 1/4W or less unless otherwise specified.
•C: panel designation.
•A: B+ Line.
•H: adjustment for repair.
•Total current is measured with no cassette installed.
•Power voltage is dc 3 V and fed with regulated dc power supply
from external power voltage jack (J401).
•Voltages and waveforms are dc with respect to ground under no-
signal (detuned) conditions.
no mark : FM
():PB
•Voltages are taken with a VOM (Input impedance 10 MΩ).
Voltage variations may be noted due to normal production toler-
ances.
•Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal production toler-
ances.
•Circled numbers refer to waveforms.
•Signal path.
F: FM
f: AM
E: PB
d: REC
N: MIC INPUT
•Abbreviation
5E : E model with the indication of the country of origin.
9E : E model without the indication of the country of origin.
CH : Chinese model
CND : Canadian model
EA : Saudi Arabia model
TW : Taiwan model
Note on Printed Wiring Board:
•Y: parts extracted from the conductor side.
•a: Through hole.
Caution:
Pattern face side: Parts on the pattern face side seen from
(Side B) the pattern face are indicated.
Parts face side: Parts on the parts face side seen from
(Side A) the parts face are indicated.
10 V/DIV, 10 µ s/DIV 1 V/DIV, 2 ms /DIV
1 T551 (REC mode)
37 Vp-p
22
µ s
2.5 Vp-p
4.5 ms
2IC301 r; (VOUT)
(PB mode)
Ver 1.2

1111
WM-GX221
6-1. BLOCK DIAGRAM – TUNER SECTION –
• SIGNAL PATH
: FM
: AM
14 8
24
2123
FM
RF AMP FM/AM
MIX AMP
FM/AM
OSC
FM
IF AMP DECODER
AMP
SWITCH
DIVIDER/
VCO
FM
DET
LEVEL
DET
AM
DET
FM
MUTE AF
BUFFER
AM
IF AMP
PD1
PD2
AM
RF AMP
7
FM-RF
IN MIX
CF2
10.7MHz
X2
10.7MHz
CF1
455kHz
12
FM
IF IN 14
13
L OUT
R OUT
151610
AM
IF IN
LP2 BAND
LP1 MO-ST
TUN LED
FM OSC
20
AM OSC
L1
AM
FERRITE BAR
ANTENNA
FM-RF OUT
AM-RF
IN
L2
FM RF
FM/AM RF AMP, FM/AM MIX AMP,
FM/AM OSC, FM/AM IF AMP, DET, MPX
IC1
CT1-2 CV1-2
CV1
TUNING
CT1-1 CV1-1
L3
FM OSC
CT1-3 CV1-3
L4
AM OSC
CT1-4CV1-4
CT1-3, L3
FM FREQUENCY
COVERAGE
CT1-4, L4
AM FREQUENCY
COVERAGE
CT1-1, L1
AM TRACKING
CT1-2, L2
FM TRACKING
T1
AM IF
B.P.F.
CP1
ANT
A
TU L, TU R
B
11
ST LED
AGC
TUN
LED
ST
LED
DET-OUT
AF
AMP
MPX-IN
QUAD
18 17
TU VCC
EXCEPT US, CND, 5E
EXCEPT US, CND, 5E
EXCEPT US, CND, 5E
US, CND, 5E
US, CND, 5E
S1 (1/2)
DX LOCAL
FM ST MONO
BAND
D1
TU B+
S705
FM
AM
R5
JR3
JR1
C1
C2
Ver 1.2

1212
WM-GX221
6-2. BLOCK DIAGRAM –MAIN SECTION –
•SIGNAL PATH
: TUNER (FM/AM)
: TAPE PLAY
: TAPE REC
: MIC INPUT
+
–
MIC AMP, ALC
IC501 (1/2)
REC/PB AMP
IC501 (2/2)
PRE AMP, POWER AMP, MEGA-BASS
IC301 (1/2)
POWER AMP
IC151
ANT
A
TU L, TU R
TU L TU R
B
S704
(TAPE POWER)
(ON at FF/REW/PLAY modes.)
S703
FUNCTION
SP151
(SPEAKER L-CH)
(SPEAKER R-CH)
SP251
POWER MUTE
SWITCH
Q707
MIX-OUT (L)
MIX-OUT (R)
POWER
IN (L)
POWER
IN (R)
POWER
OUT (L)
POWER
OUT (R)
POWER OUT (COM)
VREF
L
R
MIX-IN (L)
MIX-IN (R)
PRE-OUT (L)
L-CH
HE901
(ERASE)
FWDIN (L)
REVIN (L)
HRP901
(REC/PB)
REC VCC
TU B+
BUF
IN (L) PB OUT (L)
REC
OUT (L)
BUF
IN (R)
MIC
IN (L) MIC OUT (L)
MIC
IN (R)
PRE-NF (R)
PRE-NF (L)
15
13 16
+
–18
+
–3
+
–
6
85
1
POWER MUTE
21
SYSTEM
15
8
6
18
20
16
25
24
23
22
30
29
5
9
10
15
8
2
14
13
16
21
19
+
+
+
+
ALC MIC
AMP PB AMP
REC AMP
MIC
OUT (R) 17
ALC MIC
AMP
RIPPLE
FILTER
Q401, 403
B+ SWITCH
Q501, 502
B+ SWITCH
Q701,715
B+ SWITCH
Q712, 713
PRE AMP
Q152
PRE AMP
Q252
START/STOP
CONTROL SWITCH
REC
BIAS OSC
Q553
PRE MUTE
SWITCH
Q704
SWITCH
Q402
SWITCH
Q710
SWITCH
Q453
TAPE EQ
SWITCH
Q301
AVLS
SWITCH
Q302
NF
DET
CONTROL
L.B-SW
32
LOW
BOOST
J501
(PLUG IN POWER)
MIC
FLAT MIC
RV301
VOL
SWITCH
Q552
PB
OUT (R)
REC
OUT (R)
9
3
EQ
AMP POWER
AMP
POWER
AMP
POWER
AMP
MODE
CONTROL
CIRCUIT
PB AMP
REC AMP
11
12
PW SW
REC SW
R-CH
S301 (1/4)
S301 (2/4)
REC PB
(REC/PB)
REC PB
(REC/PB)
REC PB
S301 (4/4)
(REC/PB)
S701 (2/2)S701 (1/2)
REC PB
S301 (3/4)
(REC/PB)
NORM
LIMIT
CrO 2 /METAL
NORM
S1 (2/2)
OFF
ON
OFF
ON
SOUND BOOST
S303
NORM
DOUBLE
2X REC TIME
S601
AVLS
S304
PAUSE
S702
PRE-OUT (R)
FWDIN (R)
REVIN (R)
VREF
VREF
7
11
12
13
EQ
AMP
+
–
+
–
+
–
VREF
MIX 2
MIX 1
T551
BIAS OSC
S551
ISS
3
2
1
J301
(HEADPHONE)
i
i
+
–
SPEED
CONTROL
MOTOR
CONTROL SWITCH
Q601, 602
MOTOR
BRAKE SWITCH
Q708, 716
CAPSTAN/REEL
MOTOR DRIVE
IC301 (2/2)
M601
(CAPSTAN/REEL) MOTOR
DRIVE
CIRCUIT
SWITCH &
LOGIC
CIRCUIT
BIAS
REFERENCE
VOLTAGE
OSC
CIRCUIT
TH601
TAPE SPEED
(NORM)
RV601
TAPE SPEED
(DOUBLE)
RV602
S/S
M-VREF
IN+
COMPARATOR
VSP
OUT
OSC
3
34
47
35
36
37
WOUT
41
VOUT
40
UOUT
WV
U39
SPEAKER
DRY BATTERY
SIZE ‘‘AA’’
(IEC DESIGNATION R6)
2PCS. 3V
RADIO
TAPE
(RADIO OFF)
D401
J401
DC IN 3V
–+
MIC501
Q551
ISS
SWITCH
MAIN VCC
LINE SW
PB/REC
TU B+
TU B+
PB/REC
PB/REC
PB/REC
PB/REC
PB/REC
PB/REC
PB/REC PAUSE
D701
MAIN VCC
MAIN VCC
MAIN VCC
MAIN VCC
MAIN VCC
MAIN VCC
MAIN VCC
MAIN VCC
BATT B+
COM
Q702
Q703, 711
MIC B+
REC VCC
REC VCC
TU VCC
MAIN VCC BATT B+
BATT B+
TU B+
H/P MUTE
SHUT DOWN
H/P MUTE
SWITCH
Q705
PB MUTE
SWITCH
Q452
H/P MUTE
+
REC/BATT

1313
WM-GX221
6-3. PRINTED WIRING BOARDS
IC151
IC501
IC301
IC1
X2
CF2
CF1
Q707
–1 –2
/REEL
SOUND BOOST
EXCEPT
US, CND,
5E
US, CND, 5E
EXCEPT
US, CND, 5E
US, CND, 5E
US, CND, 5E
12
A
B
C
D
E
F
G
H
345678910111213
•Semiconductor Location
Ref. No. Location
D1 B-4
D401 C-12
D701 C-7
IC1 F-3
IC151 D-8
IC301 C-2
IC501 E-9
Q152 B-7
Q252 B-7
Q301 D-2
Q302 B-3
Q401 A-1
Q402 A-2
Q403 A-1
Q452 E-9
Q453 E-8
Q501 E-1
Ref. No. Location
Q502 E-1
Q551 F-1
Q552 E-1
Q553 E-1
Q601 B-1
Q602 B-2
Q701 D-1
Q702 C-8
Q703 D-1
Q704 C-7
Q705 B-3
Q707 B-7
Q708 B-6
Q710 D-1
Q711 D-2
Q712 E-6
Q713 E-4
Q715 E-1
Q716 B-6
Ver 1.2

1414
WM-GX221
6-4. SCHEMATIC DIAGRAM – MAIN BOARD (1/2) –
IC B/D
(DOUBLE)
(DOUBLE)
3.3k
47
0.022
220p
470p
(US, CND, EA, 5E)
• Refer to page 10 for Waveforms. • Refer to page 16 for IC Block Diagram.
Ver 1.2

1515
WM-GX221
6-5. SCHEMATIC DIAGRAM – MAIN BOARD (2/2) –
IC B/D IC B/D
IC B/D
10.7MHz
10.7MHz
2200p
2200p
47k
1k
0.1
0.1
US, CND, 5E
EXCEPT US, CND, 5E
(US, CND)
(EXCEPT US, CND, EA) EXCEPT US, CND, 5E (US, CND, EA, 5E) (US, CND, 5E)
(EXCEPT US, CND, 5E) (US, CND, EA, 5E)
US, CND, 5E
EXCEPT US, CND, 5E
• Refer to page 16 for IC Block Diagrams.
Ver 1.2

1616
WM-GX221
6-6. IC BLOCK DIAGRAMS
IC1 TA2111FN (EL)
IC151 LM4863MT
IC301 LB8115W-NA-TLM IC501 TA8155FN (ER)
24 23 22 21 20 19 18 17 16 15 14
1110987654321 12
13
AM
MIX
FM
MIX
AM
OSC
FM
OSC
AF
BUFF
AM
DET
FM
IF
AM
IF
LEVEL
DET
FM
DET
TUN
LED ST LED
AGC
FM
RF
FM-RF IN GND MIX AGC VCC 2 GND2 TUN- LED ST-LED QUADLPF3 AM
IF IN FM IF IN
FM
MUTE
ST/MO
FM/AM
AF
VCO
DECODE
DIVIDE
AM-RF IN FM-RF OUT FM OSC AM OSC AFC LP2
BAND LP1
MO-ST L OUT R OUTVCC 1 DET-OUT MPX-IN
5
6
7
8
9
10
4
3
2
1
16
15
14
13
12
11
17
18
19
20
SHUTDOWN
+OUT A
-OUT A
GND
GND
GND
VDD
-IN A
+IN A
GND
HP-IN
+OUT B
-OUT B
BYPASS
GND
GND
VDD
-IN B
+IN B
GND
CONTROL
CIRCUIT
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. PIN(R)
H.PIN(L)
DET-OUT
M-VREF
IN
+
VSP
MIX-IN(R)
MIX-IN(L)
L.B-SW
M-GND
R.P-VREF
SYSTEM
POWER-OUT(L)
POWER-GND
M-VCC DR WOUT MPGND 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)
FWDIN(R)
REVIN(R)
REVIN(L)
FWDIN(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.
+
–
5
6
7
8
9
10
11
12
4
3
2
1
20
19
18
17
16
15
14
13
21
22
23
24
VCC (REC)
REC OUR (L)
REC OUT (R)
VREF
PB NF (L)
PB OUT (L)
PB OUT (R)
PB NF (R)
REC SW
PW SW
PB IN (L)
PB IN (R)
ALC
VCC
MIC NF (L)
MIC IN (R)
MIC NF (R)
MIC OUT (R)
MIC OUT (L)
LINE SW
BUF IN (L)
BUF IN (R)
MIC IN (L)
GND
ALC
DET
ALC
VREF
RADIO / TAPE
ALC
REC / PB
PW SW
REC AMP
PB AMP
PB AMP

SECTION 7
EXPLODED VIEWS
NOTE:
•-XX, -X mean standardized parts, so they may
have some differences 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.
17
WM-GX221
•Abbreviation
5E : E model with the indication of the
country of origin.
9E : E model without the indication of
the country of origin.
CH : Chinese model
CND : Canadian model
EA : Saudi Arabia model
TW : Taiwan model
7-1. OVERALL SECTION
Ref. No. Part No. Description Remarks Ref. No. Part No. Description Remarks
13-237-138-01 POINTER
23-237-137-01 GEAR (C)
33-237-136-01 GEAR (B)
43-237-152-01 HOLDER (GEAR)
63-237-135-01 GEAR (A)
*7A-3021-657-A MAIN BOARD, COMPLETE (EA)
*7A-3021-658-A MAIN BOARD, COMPLETE (US, CND)
*7A-3021-667-A MAIN BOARD, COMPLETE (E, 9E, CH, TW)
*7A-3021-668-A MAIN BOARD, COMPLETE (5E)
83-234-570-01 BUTTON (REW)
93-234-569-01 BUTTON (FF)
10 3-234-568-01 BUTTON (PLAY)
11 3-235-589-01 BUTTON (STOP)
12 3-235-588-01 BUTTON (REC)
14 3-237-121-01 CABINET (CENTER) (EA, 9E, CH, TW)
14 3-237-121-11 CABINET (CENTER) (US, CND, 5E)
16 X-3381-403-4 HOLDER SUB ASSY, CASSETTE (EXCEPT 9E)
16 X-3381-416-1 HOLDER SUB ASSY, CASSETTE (9E)
17 3-237-140-01 SPRING (TORSION)
18 3-237-139-01 COVER, JOINT
19 3-237-132-01 KNOB (MODE)
20 3-237-133-01 KNOB (SOUND)
21 3-237-119-01 PANEL (CABINET FRONT)
22 3-237-149-01 TERMINAL (-), BATTERY
23 3-237-150-01 TERMINAL (+), BATTERY
24 3-893-942-41 SCREW (B1.7X4), TAPPING
25 3-318-203-91 SCREW (B1.7X9), TAPPING
26 3-893-942-01 SCREW
27 3-893-942-01 SCREW (B1.7), TAPPING
28 3-939-590-16 SCREW (IB LOCK)
29 3-318-203-63 SCREW (1.7X3), TAPPING (B)
30 3-345-648-81 SCREW (M1.4), TOOTHED LOCK
31 3-375-114-01 SCREW (M1.4)
#1 7-627-552-08 SCREW,PRECISION +P 1.7X2.5
24
2
1
3
4
6
a
a
b
b
7
8
9
10
11
12
3
23
22
14
16
17
18
21
19
20
30
#1
31
25
26
27
24
28
29
24
24
MT-WMGX221-175
CABINET (FRONT) SECTION
Ver 1.2

18
WM-GX221
7-2. CABINET (FRONT) SECTION
Ref. No. Part No. Description Remarks Ref. No. Part No. Description Remarks
51 3-237-123-01 WINDOW (DIAL) (EA)
51 3-237-123-11 WINDOW (DIAL) (E, 9E, CH, TW)
51 3-237-123-21 WINDOW (DIAL) (US, CND, 5E)
52 3-237-201-01 SHEET, ADHESIVE
53 3-237-130-01 KNOB (BAND)
54 3-237-131-01 KNOB (PAUSE)
55 3-237-120-01 CABINET (FRONT)
56 3-237-134-01 KNOB (AVLS)
*57 1-683-530-11 SUB BOARD
58 1-823-584-11 CABLE, FLEXIBLE FLAT (6 CORE)
59 3-237-128-01 CUSHION (MIC)
60 3-239-558-01 SPRING (GROUND)
61 3-237-125-01 LID, BATTERY CASE
62 3-237-129-01 KNOB (SP/HP)
63 3-237-126-01 LENS
64 3-237-151-01 PANEL (MIC)
65 3-237-127-01 KNOB (TAPE SPEED)
66 1-542-481-11 MICROPHONE, ELECTRET CAP
67 3-034-792-01 SCREW, TAPPING (B2.0)
68 3-318-382-41 SCREW (1.7), TAPPING
MIC501 1-542-307-11 MICROPHONE (FLAT MIC)
SP151 1-544-993-11 SPEAKER (3.6cm) (L)
SP251 1-544-993-11 SPEAKER (3.6cm) (R)
51
52
54
55
56
53
65
64
62
59
57
58
60
63
67
67
68
66
SP151
SP251
MIC501
61
Ver 1.2

19
WM-GX221
Ref. No. Part No. Description Remarks Ref. No. Part No. Description Remarks
7-3. MECHANISM DECK BLOCK-1
(MT-WMGX221-175)
101 3-704-197-01 SCREW (M1.4), SPECIAL HEAD
102 3-234-857-01 BELT (CAP)
104 X-3379-877-1 FLY ASSY (AR), CAPSTAN
105 3-386-694-01 WASHER
106 3-029-278-01 WASHER
107 3-029-275-01 WASHER (STOPPER N)
108 3-703-816-73 SCREW (M1.4), SPECIAL HEAD
109 3-234-861-01 GUIDE (ARO), TAPE
110 3-019-776-01 GEAR (REEL-S)
111 3-703-816-24 SCREW (M1.4X2.5), SPECIAL HEAD
112 X-3379-882-1 PINCH (N) ASSY, ARM
113 3-703-925-21 SCREW (M1.4)
M601 1-763-772-11 MOTOR, DC (CAPSTAN/REEL)
HE901 1-500-232-11 HEAD, MAGNETIC (ERASE)
HRP901 1-500-718-11 HEAD,MAGNETIC(REC/PB)
A (Included in Ref. No.151)
HRP901
HE901
M601
110
112
101
102
104
105
108
111
113
109
107
106
z
not
supplied
not
supplied

20
WM-GX221
7-4. MECHANISM DECK BLOCK-2
(MT-WMGX221-175)
(Including A)
152
153
154
155
156
157
159
160 161
162
164
165
166
172
169
170
171
151
z
Ref. No. Part No. Description Remarks Ref. No. Part No. Description Remarks
151 X-3381-206-1 CHASSIS ASSY (ARO)
152 3-225-385-01 GEAR (B)
153 3-229-063-01 SPRING (UD) (R), COMPRESSION
154 3-019-778-01 SLEEVE (MS)
155 3-728-091-01 WASHER, STOPPER
156 3-225-427-01 WASHER, LEVER
157 3-225-384-01 GEAR (A)
159 3-225-395-01 LEVER (REW ROTARY)
160 X-3380-677-1 LEVER (E DETECTION) ASSY
161 3-229-064-01 WASHER, STOPPER
162 3-225-393-01 LEVER (SHUT/OFF)
164 3-321-813-71 WASHER, COTTER POLYETHYLENE
165 X-3379-881-1 CLUTCH ASSY (AR)
166 3-315-384-31 WASHER, STOPPER
169 3-225-388-01 GEAR (D)
170 3-225-394-01 LEVER (FF ROTARY)
171 3-225-444-01 SPRING (FR ROTARY), TENSION
172 3-344-901-01 WASHER, STOPPER