Sony WMFX-373 Service manual
WM-FX373/FX375
SERVICE MANUAL
Ver 1.2 2004.03
Photo: WM-FX373
Dolby noise reduction manufactured under license
from Dolby Laboratories Licensing Corporation.
“DOLBY” and the double-D symbol ; are trademarks of Dolby Laboratories Licensing Corporation.
SPECIFICATIONS
• Frequency range
FM: 65.0 – 107.9 MHz (East European Model)
87.5 – 108 MHz (Italian, Saudi Arabia Model)
87.6 – 108 MHz (US, Canadian Model)
87.6 – 107.9 MHz (Other Model)
AM: 526.5 – 1,606.5 kHz (Italian, Saudi Arabia Model)
530 – 1,710 kHz (US, Canadian Model)
531 – 1,602 kHz (Other Model)
• Power requirements
3V DC batteries R6 (AA) × 2/External DC 3V power sources
• Dimensions
88.5 × 118.6 × 38.2 mm
(3 1/2 × 4 3/4 × 1 9/16 inches) (w/h/d) incl. projecting parts and controls
• Mass
Approx. 170 g (6.0 oz)
Approx. 250 g (8.9 oz) incl. batteries and a cassette
• Supplied accessories
Stereo headphones or Stereo earphones (1)/Belt clip (1)
US Model
WM-FX375
Canadian Model
Tourist Model
WM-FX373
AEP Model
E Model
Chinese Model
WM-FX373/FX375
Model Name Using Similar Mechanism NEW
Tape Transport Mechanism T ype
MT-WMEX372-114
Design and specifications are subject to change without notice.
9-923-344-12 Sony Corporation
2004C05-1 Personal Audio Company
© 2004.03 Published by Sony Engineering Corporation
RADIO CASSETTE PLAYER
TABLE OF CONTENTS
SERVICING NOTES
1. GENERAL ................................................................... 2
2. DISASSEMBLY ......................................................... 3
3. MECHANICAL ADJUSTMENTS....................... 7
4. ELECTRICAL ADJUSTMENTS......................... 7
5. DIAGRAMS
5-1. Block Diagram ................................................................ 10
5-2. Printed Wiring Board ...................................................... 12
5-3. Schematic Diagram ......................................................... 15
6. EXPLODED VIEWS ................................................ 21
7. ELECTRICAL PARTS LIST ............................... 24
This section is extracted from
instruction manual.
SECTION 1
GENERAL
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 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.
– 2 –
• This set can be disassembled in the order shown below.
y
SECTION 2
DISASSEMBLY
CABINET (REAR)
ASS’Y
DIAL POINTER
SETTING
Note: Follow the disassembly procedure in the numerical order given.
MAIN BOARD
CABINET (REAR) ASS’Y
3
Remove the cabinet (rear) ass’y
(Release all claw
1
two screws
×
9)
(B1.7
B
to K in alphabetical order.)
J
I
K
cabinet (rear) ass’
B
MECHANISM DECK
(MT-WMEX372-114)
CASSETTE HOLDER ASS’Y
NOTE FOR INSTALLATION
2
Insert the precision screw
driver (1.4 mm flat-blade) in to
the slit at claw
the claw.
C
A
and release
BELT, MOTOR (M901)
MAGNETIC HEAD (HP901)
MEGA BASS
UNIT
A
H
G
MAIN BOARD
3
Flexible board
(CN301)
F
D
E
4
toothed lock (WH) screw
(M1.4)
2
Flexible board
(CN302)
1
Remove four solders
of motor (M901).
6
main board
5
two claws
– 3 –
MECHANISM DECK (MT-WMEX372-114)
d
A
2
Remove the mechanism deck
(MT-WMEX372-114) to direction
of the arrow A.
1
two claws
BELT, MOTOR (M901), MAGNETIC HEAD (HP901)
1
5
magnetic
head (HP901)
belt
3
motor (M901)
4
two screws (M1.4)
– 4 –
2
two special hea
screws (M1.4)
CASSETTE HOLDER ASS’Y
A
B
3
Cassette holder ass’y
4
spring
(torsion)
2
Portion B to release
the hinge plate.
1
Insert a precision screw driver (1.4 mm flat-blade)
vertically in to portion
A
to release the hinge plate.
f
NOTE FOR INSTALLATION
Note: Follow the assembly procedure in the numerical order given.
A
3
Cassette holder ass’y
1
2
Attach the spring (torsion)
as shown in the figure.
Insert the spring (torsion)
in the ditch to direction o
the arrow A.
– 5 –
MEGA BASS UNIT
Note for installation:
Check that two switches are latched
with dolby knob and M/B knob when
carrying out installation of the mega bass unit.
dolby knob
M/B knob
3
two claws
4
Remove the mega bass
unit to direction of
the arrow
A
.
1
two knobs
(rotary)
2
stopper
A
3
three claws
5
flexible board
two switches
DIAL POINTER SETTING
Note: Follow the assembly procedure in the numerical order given.
1
Turn the knob (TUNE)
fully in the arrow direction.
pointer
fig.
2
Mount the pointer
as shown in the figure A.
guide rib
A
– 6 –
SECTION 3
r
label (model)
RV601
MECHANICAL ADJUSTMENTS
SECTION 4
ELECTRICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcoholmoistened
swab:
playback head pinch roller
capstan 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 (2.5 V) unless otherwise noted.
Torque Measurement
Mode Torque meter Meter reading
FWD
FWD less than 2 g•cm
Back Tension (less than 0.03 oz•inch)
REV
REV less than 2 g•cm
Back Tension (less than 0.03 oz•inch)
FF, REW CQ-201B
CQ-102C
CQ-102RC
Tape Pulling Force Measurement
Mode Torque meter Meter reading
FWD CQ-403A
REV CQ-403R
20 – 42 g•cm
(0.28 – 0.58 oz•inch)
20 – 42 g•cm
(0.28 – 0.58 oz•inch)
more than 50 g•cm
(more than 0.69 oz•inch)
more than 30g
(more than 0.41 oz)
PRECAUTION
• Supplied voltage: 2.5 V (DC)
• Switch and control position
NORM CrO2/METAL·ST/MONO switch: NORM·ST
(EXCEPT US, Canadian, 5E, 6E model)
NORM CrO2/METAL·DX/LOCAL switch: NORM·DX
(US, Canadian, 5E, 6E model)
VOLUME control: maximum
TONE CONTROL HIGH and LOW: mechanical center
AVLS switch: NORM
MEGA BASS switch: OFF
DOLBY NR switch: OFF (FX375 only)
FM/AM/TAPE (RADIO OFF) switch: TAPE (RADIO OFF)
Test tape
Type Signal Used for
WS-48A 3 kHz, 0 dB Tape Speed Adjustment
0 dB=0.775 VT APE SECTION
Tape Speed Adjustment
Procedure:
test tape
WS-48A
(3kHz, 0 dB)
FX373 (Canadian): 32
others: 16
Ω
set
i
jack
Ω
frequency counte
+
–
1. Playback WS-48A (tape center part) in the FWD state and adjust RV601 so that the frequency counter reading becomes
3,000 ± 15 Hz.
2. Playback WS-48A (tape center) in the REV state.
Check that the frequency counter reading is within 1.0% of
the reading of step 1.
Adjustment Location:
– 7 –
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