Sony WM-FX271FP User manual

1
Ver 1.0 2003. 07
Model Name Using Similar Mechanism WM-FX271
Tape Transport Mechanism Type MF-WMFX171-114
SERVICE MANUAL
US Model
WM-FX271FP
RADIO CASSETTE PLAYER
Frequency range
FM: 87.5 – 108 MHz
AM: 530 – 1,710 kHz
Power requirements
3 V DC batteries R6 (AA) ×2/External DC 3 V power sources
Dimensions
91.4 ×115.5 ×35.9 mm (3 5/8 ×4 5/8 ×1 7/16 inches) (w/h/d) incl.
projecting parts and controls
Mass
Approx. 150 g (5.3 oz.)
Approx. 230 g (8.2 oz.) incl.batteries and a tape
Supplied accessories
Stereo headphones or Stereo earphones (1)
Design and specifications are subject to change without
notice.
SPECIFICATIONS
Sony Corporation
Personal Audio Company
Published by Sony Engineering Corporation
9-961-044-01
2003G04-1
© 2003. 07
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.
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.

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TABLE OF CONTENTS
1. GENERAL ........................................................................... 3
2. DISASSEMBLY
2-1. Cabinet (Front) Sub Assy ....................................................4
2-2. Main Board ......................................................................... 5
2-3. Holder (Sub) Assy, Cassette ................................................5
2-4. Mechanism Deck................................................................. 6
2-5. Belt and Motor .................................................................... 6
3. MECHANICAL ADJUSTMENTS ................................. 7
4. ELECTRICAL ADJUSTMENTS
Tape Section ............................................................................ 7
Tuner Section........................................................................... 8
5. DIAGRAMS
5-1. IC Pin Description............................................................. 10
5-2. Block Diagram .................................................................. 11
5-3. Printed Wiring Board ........................................................ 12
5-4. Schematic Diagram ........................................................... 13
6. EXPLODED VIEWS
6-1. Cabinet Section ................................................................. 15
6-2. Tape Mechanism Section-1 ............................................... 16
6-3. Tape Mechanism Section-2 ............................................... 17
7. ELECTRICAL PARTS LIST ........................................ 18
WM-FX271FP
zUNLEADED SOLDER
Boards requiring use of unleaded solder are printed with the lead
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size.)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
• Unleaded solder melts at a temperature about 40°C higher than
ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350°C.
Caution: The printed pattern (copper foil) may peel away if the
heated tip is applied for too long, so be careful!
•Strong viscosity
Unleaded solder is more viscous (sticky, less prone to flow)
than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.
•Usable with ordinary solder
It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.

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WM-FX271FP
SECTION 1
GENERAL This section is extracted
from instruction manual.
AVLS
VOLUME
xSTOP
MFF
NPLAY
mREW
TUNING +/–
HOLD
i
MEGA BASS
RADIO ON/OFF
BAND
DC IN 3V
NORM/CrO 2 /METAL
DX/LOCAL or
NORM/CrO
2 /METAL
ST/FM MONO
1-5 (preset)
*
*The button has a tactile dot.
Location of parts and controls

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WM-FX271FP SECTION 2
DISASSEMBLY
• The equipment can be removed using the following procedure.
Note : Follow the disassembly procedure in the numerical order given.
2-1. CABINET (FRONT) SUB ASSY
Note : When installing, fit the knobs and switches.
1 Insert the precision screwdriver
(1.4 mm flat-blade) into the slit
at claw A and release the claw.
2 Remove the cabinet (front) sub assy.
(Release all claws B to N in
alphabetical order.)
Cabinet (front) sub assy Main boardSet Holder (sub) assy, cassette Belt and Motor
Mechanism deck
A
cabinet (front) sub assy
holder (sub) assy, cassette
B
C
D
E
FHI
J
K
S71
6
G
L
M
N
cabinet (front) sub assy
Note : When removing the cabinet, put cloth
on the end of a screwdriver or use a
polyacetal driver to avoid damage to
the cabinet.

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WM-FX271FP
2-2. MAIN 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.
4two claws 1HEAD FLEXIBLE board (CN301)
2Unsolder the 4 places.
5MAIN board
3screw (M1.4), toothed lock (WH)
1Open the holder (sub) assy, cassette.
4holder (sub) assy, cassette.
A
B5spring (torsion
)

6
WM-FX271FP
2-4. MECHANISM DECK
2-5. BELT AND MOTOR
1Insert the precision screwdriver
(1.4 mm flat-blade) into the slit
and release three claws.
2Remove the mechanism dec
k
in the direction of the arrow.
• How to apply the belt
1belt
3motor
2two screws (screw (M1.4), toothed lock)
wheel assy (NP), capstan
belt
M901

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WM-FX271FP
SECTION 3
MECHANICAL ADJUSTMENTS
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
1.97 to 4.90 mN • m
FWD CQ-102C 20 to 50 g • cm
(0.28 to 0.69 oz • inch)
FWD less than 0.19 mN • m
Back Tension CQ-102C less than 2 g • cm
(less than 0.03 oz • inch)
more than 5.89 mN • m
FF, REW CQ-201B more than 60 g • cm
(more than 0.83 oz • inch)
0000
ijack (J301)
digital frequenc
y
counter
set
16 Ω
test tape
WS-48A
(3 kHz, 0 dB)
PRECAUTION
•Supplied voltage : 2.5V
•Switch and control position
VOLUME control : maximum
AVLS switch : NORM
• 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:
SECTION 4
ELECTRICAL 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
2,910 to 3,090 Hz
Adjustment Location:
RV601

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WM-FX271FP
ijack (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
•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 kHz
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L1 CT1
620 kHz 1,400 kHz
TUNER SECTION 0 dB = 1 µV
•FM Section
Setting:
RADIO ON/OFF switch: ON
BAND switch : FM
FM Tuning Voltage Adjustment
FM TUNING VOLTAGE ADJUSTMENT
Adjust for a 8.5 ± 0.3 (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
digital
voltmeter
TP (VT)
Main board
FM RF signal
generator
0.01 µF(FM RF IN)
Main boar
d
(GND)
ijack (J301)
set
16 Ω
level meter
(range: 0.5-5 V ac
)
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L2
87.5 MHz
•AM Section
Setting:
RADIO ON/OFF switch: ON
BAND switch : AM
AM Tuning Voltage Adjustment
AM TUNING VOLTAGE ADJUSTMENT
Adjust for a 1.1 ± 0.1 Vdc reading on digital voltmeter.
L4
530 kHz
AM IF Adjustment, AM Tracking Adjustment
Modulation: 400Hz, 30%
Output level: as low as possible

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WM-FX271FP
L3
FM TUNING
VOLTAGE
ADJUSTMENT
L2
FM TRACKING
ADJUSTMENT
L4
AM TUNING
VOLTAGE
ADJUSTMENT
T1
AM IF
ADJUSTMENT
CT1
AM TRACKIN
G
ADJUSTMENT
L1
Adjustment Location: main board
Measurement Points: main board
(FM RF IN)
(VT)
FM RF INVT

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WM-FX271FP SECTION 5
DIAGRAMS
5-1. IC PIN DESCRIPTION
• IC701 µPD17072GB-559-1A7 (SYSTEM CONTROL/LCD DRIVE)
Pin No. Pin Name I/O Pin Description
1INIT O Initialize output
2, 3 NC — Not used.
4MEGA BASS O MEGA BASS ON/OFF output (L: ON, H: OFF)
5RADIO-ON O Radio circuit power control output
6 – 8 KEY OUT1 – 3 O Key matrix output 1 – 3
9NC—Not used.
10, 11 KEY IN1, 3 I Key input 1, 3
12, 13 BTT-REF1, 2 I Reference voltage input for battery voltage check.
14 MUTE OUT O Mute output (Mute ON: L, Mute OFF: input)
15 SD I SD (with local) signal input
16 BAND O Radio band select output (AM: L, FM: input)
17 HOLD I Key hold input (Key input effect: L, Key input ineffect: H)
18 GND — Ground
19 EO O PLL error out output
20 VCO (AM) I VCO (AM) input
21 VCO (FM/TV) I VCO (FM) input
22 VDD2 — Voltage regulator for PLL.
23 VDD1 — Power supply pin
24 XO — Crystal oscillator output (75 kHz)
25 XI — Crystal oscillator input (75 kHz)
26 VDD5 — Voltage regulator for oscillation circuit.
27 VDD3 — Power supply for LCD driver.
28, 29 CAP1, 2 — Stabilized capacitor connection of crystal oscillation power supply.
30 VDD4 — Power supply for LCD driver.
31 – 34 COM0 – 3 O LCD driver common output
35 – 49 LCD0 – 14 O LCD driver output
50 CE I L: Clock stop, H: Normally operation
51 TAPE ON I At TAPE ON: H
52 BEEP O BEEP output
53 NC — Not used.
54 KEY IN2 I Key input 2
55 NC — Not used.
56 KEY IN4 I Key input 4