Sony Walkman WM-FX855 User manual

RADIO CASSETTE PLAYER
E Model
Tourist Model
Model Name Using Similar Mechanism NEW
Tape Transport Mechanism Type MT-WMEX655-125
SPECIFICATIONS
SERVICE MANUAL
WM-FX855
Dolby noise reduction manufactured under license from
Dolby Laboratories Licensing Corporation.
“ DOLBY ” and the double-D symbol aare trademarks of
Dolby Laboratories Licensing Corporation.
Photo: Black
– Continued on next page –
Tape player section and general
Frequency response (aNR switch off)
30–18,000 Hz
OutputHeadphones (2REMOTE jack)
Load impedance 8–300 ohms
Power output
3mW + 3mW at DC operation
Power requirements
1.5V DC
Rechargeable battery (NC-6WM), 1.2 V, 600mAh, Ni-Cd One R6
(size AA) battery
Battery life (Approx. hours)
Rechargeable NC-6WM
Fully charged
Playback 9
Radio/TV reception 9
Sony alkaline LR6 (WM)
Playback 36
Radio/TV reception 29
Sony R6P (SR)
Playback 10
Radio/TV reception 9
Rechargeable NC-6WM
Sony alkaline LR6 (WM)
Used together
Playback 45
Radio/TV reception 36
Dimensions
Approx. 108.7 ×80.0 ×23.5 mm (w/h/d)
WeightApprox. 150 g (Main unit)
Approx. 210 g (incl. Headphones with remote control, Recharge-
able battery NC-6WM, Tape (C-60HF)
Radio section
Frequency range
Tourist model
FM : 76–90MHz
AM : 531–1,710kHz
TV : 1–12ch (Except Korean model.)
Korean model (Area setting : Eur)
FM : 87.5–108MHz
AM : 531–1,602kHz
Design and specifications are subject to change without notice.
Ver 1.3 2001.11
9-923-252-12 Sony Corporation
2001K0500-1 Personal Audio Company
C2001.11 Published by Sony Engineering Corporation

– 2 –
TABLE OF CONTENTS
1. SERVICE NOTE....................................................... 3
2. GENERAL ................................................................... 5
3. DISASSEMBLY ......................................................... 6
4. MECHANICAL ADJUSTMENT.......................... 8
5. ELECTRICAL ADJUSTMENT............................ 8
6. DIAGRAMS
6-1. Block Diagram ................................................................ 11
6-2. Printed Wiring Board
– AUDIO Section – ......................................................... 14
6-3. Schematic Diagram
– AUDIO Section – ......................................................... 17
6-4. Schematic Diagram
– TUNER Section – ........................................................ 22
6-5. Printed Wiring Board
– TUNER Section – ........................................................ 25
6-6. IC Pin Function Description ........................................... 30
7. EXPLODED VIEWS................................................ 34
8. ELECTRICAL PARTS LIST ............................... 37
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 dur-
ing 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
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK !OR DOTTED
LINE WITH MARK !ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.

– 3 –
SECTION 1
SERVICE NOTE
Service Mode
Mode for operating the mechanism section with theAUDIO board
opened.
1. Setting
1) Refer to “Disassembly”, and remove the cabinet and open the
AUDIO board.
2) Connect the motor and plunger to the AUDIO board using
jumper wires. These can be connected easily with the use of
the extension tool (1-769-143-11) (ten in one set).
3) Turn ON the HOLDER switch (S706).
4) Input the square wave or sine wave to PH701. (See right fig-
ure.)
5) Supply 1.5 V to the ‘and ’terminals of the battery using a
regulated power supply.
2. Preset state
To set the PLAY, FF, REW modes, the preset state must be set.
1) Check that the lever (FR SW) and FWD/RVS switch (S708)
are set to the center position. If not, set the preset state as fol-
lows.
2) Move the FWD/RVS switch (S708) to the side which the lever
(FR SW) is facing.
3) The lever (FR SW) will move when the regulated power sup-
ply switch is set to OFF once and then set to ON. Move the
FWD/RVS switch (S708) according to this timing and set to
the center position.
3. FF, REW Modes
1) Check that the preset state is set and press the FF and REW
switches.
4. PLAY mode
1) Check that the preset state is set.
2) Pressing the ª·switch will move the lever (FR SW) once
towards the F side and then to the R side. Moving the FWD/
RVS switch (S708) according to this timing will set the PLAY
mode (R side). Pressing the ª·switch another time and
moving the FWD/RVS switch (S708) according to the move-
ment of the lever (FR SW) will set the PLAY ( F side) mode.
Note 1: If the above fails, perform from preset again.
Note 2: Use the ª·, π, FF, REW switches on the remote
commander as much as possible. If no remote commander,
do not touch the switches with your hands, but using a
stick with a round tip.
Note 3: When using headphones, the timing for moving the S708
can be determined from the beep sound.
Audio Board
— Side A –
Battery terminal (—)
Connect to motor
Connect to plunger CN501
IC501
IC301
Battery
terminal (+)
— Side B —
S708
FWD/RVS Switch
(FWD
← STOP → RVS)
S706
(HOLDER Switch) side F side R
Center
IC701
PH701
AF OSCILLATOR Sguare wave (Sine wave)
10 Hz —3.5 dB
AK
CE
lever (FR SW)
side F
side R center
Lever (FR SW)

– 4 –
Rotation system
Rotation system during PLAY.
gear (REEL)
(T side) gear (TB) gear (S)
clutch ass’y (M)
gear (Y)
gear (TA)
pulley (reverse)
flywheel (R) ass’y
flywheel (N) ass’y
gear (REEL)
(S side)
motor pulley
gear (NR)
(REW: right side/
FWD: left side)
Rotation system during FF.
gear (TB) gear (FR)
(FF: left side) gear (NR)
clutch ass’y (M)
motor pulley
pulley (reverse)
flywheel (R) ass’y
flywheel (N) ass’y
gear (Y)
gear (REEL)
(T side)
Rotation system during REW.
gear (NR)
gear (FR)
(REW: right side) gear (REEL)
(S side)
gear (S) motor pulley
clutch ass’y (M)
pulley (reverse
)
flywheel (R) ass’y
flywheel (N) ass’y
gear (Y)

– 5 –
SECTION 2
GENERAL
LOCATION AND FUNCTION OF CONTROLS
Tape player section and general
• Main Unit
Radio section
• Main Unit
• Headphones with Remote Control
Left Right
• Headphones with Remote Control
Left Right
1OPEN button
2Information display
3Contact for dry battery case
4Rechargeable battery case
5Tape operation buttons
6BATT indicator
7HOLD switch
8Main unit : VOLUME knob
Remote control : VOL knob
9Åa (Tape direction),
BL SKIP (Blank skip) switch
!º a(DOLBY) NR switch
!¡ 2REMOTE jack
!™ Micro plug
!£ SOUND/AVLS button
1ENTER button
2ASP (Auto Station Preset) button
3PRESET +, – button
4TUNE +, – button
5p, RADIO OFF button
6FM ST/MONO switch
7BAND, RADIO ON button

– 6 –
CASE ASS’Y
SECTION 3
DISASSEMBLY
AUDIO BOARD
• This set can be disassembled in the order shown below.
1 two screws
(IB lock)
3 Remove the case ass’y
to direction of the arrow
A .
2 two screws
(IB lock)
2 screw (IB lock)
6 two screws
(M1.7
× 3.0)
3 Remove four solders.
5 Remove four solders.
2 tuner flexible board
9 sw cover
8 AUDIO board
4 Remove two solders.
7 screw
(IB lock)
1 head flexible board
CASE ASS’Y
(page 6)
AUDIO BOARD
(page 6) MECHANISM DEC
K
(page 7)
LID ASS’Y CASSETTE
(page 7)
Note: Follow the disassembly procedure in the numerical order given.

– 7 –
LID ASS’Y, CASSETTE
MECHANISM DECK
5 lid ass’y, cassette
4 serrat
(IB lock)
4 serrat (IB lock)
2 tuner flexible boar
d
3 screw
(IB lock)
1 Open the cassette lid.
ornament ass’y, reel
2 Remove the mechanism deck
to direction of the arrow
A .
A
1
1

– 8 –
SECTION 4
MECHANICAL ADJUSTMENTS SECTION 5
ELECTRICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab: playback head pinch roller
rubber belts capstan
2. Demagnetize the playback head with a head demagnetizer.
(Do not bring the head demagnetizer close to the erase head.)
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 (1.3 V) unless otherwise noted.
Torque Measurement:
Mode Torque meter Meter reading
FWD 18 – 30 g•cm
CQ-102C (0.25 – 0.41 oz•inch)
FWD 0.7 – 2.0 g•cm
back tension (0.006 – 0.027 oz•inch)
REV CQ-102RC
18 – 30 g•cm
(0.25 – 0.41 oz•inch)
REV 0.7 – 2.0 g•cm
back tension (0.006 – 0.027 oz•inch)
FF CQ-201B more than 35g•cm
REW (more than 0.49 oz•inch)
Type Signal Used for
WS-48A 3 kHz, 0 dB Tape Speed Adjustment
Tape Speed Adjustment
Procedure:
1. Playback WS-48A (tape center part) in the FWD state and ad-
just RV601 so that the frequency counter reading becomes 3,015
± 10 Hz.
2. Playback WS-48A (tape center) in the REV state.
Check that the frequency counter reading is within 2.5% of the
reading of step 1.
Adjutment Point:
AUDIO BOARD – Side A –
PRECAUTION
1. Specified voltage : 1.3 V (DC)
2. Switch position
aNR switch : OFF
DIR MODE switch : a
TAPE SECTION
Test tape
Test tape
WS-48A
(3 kHz, 0 dB) frequency counter
+
—
32
Ω
set
2 REOMTE jack
RV601
ND501

– 9 –
TUNER SECTION
AM SECTION
Setup:
BAND switch: AM
AM RF signal
generator
Put the lead-wire
antenna close to
the set.
400 Hz 30 %
AM modulation
Output level: as low as possible
FM SECTION
Setup:
BAND switch: FM
FM RF signal
generator
TP1 (ANT)
TP23 (ANT GND
)
(see page 10)
0.01
µ FTUNER Board
1 kHz 100 % FM modulation
frequency devition
± 75 kHz
Output level: as low as possible
level mete
r
2 REMOTE jack
32
Ω
set
Connection:
AM Frequency coveage adjustment
digital voltmeterTUNER Board
TP21 (VT)
(see page10)
+
—
Caution:
Before the FM measurement, remove a chip ceramic capacitor C22
in the ANT line. Reconnect it after measure ment.
•For the tracking adjustment, repeat is 2 or 3 times, then end
with adjustment of trimmer capacitor.
[TUNER Board]
C22
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T2 450 kHz
AM FREQUENCY COVERAGE ADJUSTMEN
Adjusting device Frequency display Digital Voltmeter
reading
T1 531 kHz 1.3 ± 0.05 V
Confirm 1,710 kHz 7.95 ± 0.5 V
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L8 621 kHz
CT1 1,404 kHz
FM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
L5 10.7 MHz

– 10 –
VCO Adjustment
connection:
frequency counter TUNER Board
TP25 (19 kHz
)
150 k Ω
+
—
• Adjusting Location
[TUNER Board]
TP25
(19 kHz)
TP23
(ANT GND)
TP1
(ANT)
T2
AM IF Adjustment
T1
AM Frequency coverage
Adjustment L5
FM IF Adjustment
TP21
(VT)
RV1
VCO Adjustment
L8
CT1
AM
Tracking
Adjustment
VCO Adjustment
Adjusting device Frequency display Frequency counter
reading
RV1 78.00 MHz 19.00 kHz ± 0.05 kHz

– 21 –
•Waveforms
– AUDIO Section – –TUNER Section –
1IC501 @ª (XIN)
1V/DIV, 10 µs/DIV
2IC701 5(X0)
2V/DIV, 200 ns/DIV
1T3 4
1V/DIV, 100 ns/DIV
2T3 1
10V/DIV, 100 ns/DIV
2.4 Vp-p
2 ns
20.4 Vp-p
18 ns
1.8 Vp-p
75 kHz
4 Vp-p
4 MHz

– 27 – – 28 –
•IC Block Diagrams
– AUDIO Section –
IC301 TA2103F
+
–
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
47 46 45 44 43 42 41 40 39 38 37 36 35 34 33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16151413
12
11
10
987654321
AGC
DET BASS
SW
BST
RIPPLE
FILTER MTL
DRV
PRE
V REF PRE
CH-A CH-B
AGC DET
AMS
SW
EK
CH-A NR
CH-B
NR
C
H
DG
F
SW
ALC
BEEP
+
–
PW
B
+
–
PW A
+
–
PW C
V / I PW
V REF
ADD B ADD A
MIX
PRE NF-L
PRE NF-R
F/R SW
DET 1
AMS OUT
AMS HPF
PRE SW
EK IN-R
BUF IN-R
NR SW
BUF IN-L
EK IN-L
PRE OUT-L
PRE OUT-R
MTL DRV-L
MTL DRV-R
HIGH SW BST SW PW IN-C BST OUT BST NF EQ-R PW NF-R VCC1 PRE GND 3 IN-R REV IN-R FWD DC SRV-R PRE VREF DC SRV-L IN-R FWD IN-L REV
DET 2
AGC IN
RF OUT
BASE
VCC
PW GND
PW OUT-R
PW OUT-C
PW OUT-L
PW SW
MUTE SW
BEEP
TC
AVLS DET
AVLS IN
AVLS OUT
EQ-L
PW NF-L
PW IN-L
PRE GND
PW IN-R
PW VREF
RF IN
NR OUT-R
SC IN-R
HPF-R
RECT-R
PRE GND 2
RECT-L
HPF-L
SC IN-L
NR OUT-L
B
IC703 PST9010NL
IC704 PST9015NL
IC601 MM1279XVBE
IC801 MPC1850DTBEL
2
3
4
5
6
7
89
10
14
13
12
11
C3H
VG
C2L
NC
RO
NC
RI
NC
C2H
C1H
GND
COL
VC
COH
VOUT
MODE
VC VC
VC
F/F F/F f1
f2
VC
f1/f2 CHARGE PUMP
CIRCUIT
x 2
16
15
1
OSC
CHARGE PUMP
CIRCUIT
x 4

– 29 –
–TUNER Section –
IC1 TA8182FN
IC2 TA2022AFN-EL

– 30 –
1 RADIO CTL O Output of RADIO control signal “ H ”: RADIO ON
2 AM CTL O Output of AM control signal
3 TV CTL O Output of TV control signal
4 CS O Output of clock to EEPROM
5 NC — Not used for this set (Open)
6 E CLK O Output of serial clock to EEPROM
7 LED CTL O Output of LED control signal “ H” : LED ON
8 RDATA O Output of data to remote controller
9 ASP CTL O Output of auto station preset control signal
10 ST/MONO CTL O Output of FM STEREO/MONO control signal “ L ”: STEREO, “ H ”: MONO
11 RMUM I Remote controller provided/not provided “ H ”: Provided, “ L ”: Not provided
12 NC — Not used for this set (Open)
13 DOLBY/ST SW I Input of DOLBY/ST switching signal
14 KEY IN I Key input terminal
15 BATT DET I Not used for this set (fixed at “ L ”)
16 E DATA I Input of serial data from EEPROM
17 MUTE CTL O Output of audio MUTE control signal “ L ”: MUTE ON
18 DOLBY CTL O Output of DOLBY ON/OFF control signal “ L ”: DOLBY ON
19 IF DET I Input of IF detection signal
20 GND — Ground terminal
21 GND — Ground terminal
22 EO O Output of PLL error signal
23 VCOL I Input of local oscillating frequency (direct frequency dividing system)
24 VCOH I Input of local oscillating frequency (pulse swallow system)
25 VREG0 — Output of PLL requlator
26 VDD — Power supply terminal
27 VDD — Power supply terminal
28 XOUT O Output of clock (75 kHz)
29 XIN I Input of clock (75 kHz)
30 VREG1 — Output of oscillating circuit regulator
31 VREG0 — LCD drive power supply terminal
32 CAP0 — LCD drive power supply terminal
33 CAP1 — LCD drive power supply terminal
34 VLCD1 — LCD drive power supply terminal
35-37 COM0-2 O Output of common signals to the LCD
38 NC — Not used for this set (Open)
39 COM3 O Output of common signals to the LCD
40-44 LCD0-4 O Output of segment signals to the LCD
45 NC — Not used for this set (Open)
46-53 LCD5-12 O Output of segment signals to the LCD
6-6. IC PIN FUNCTION DESCRIPTION
• AUDIO BOARD IC501 µPD17073GB-912-9EV (SYSTEM CONTROL (SUB))
Pin No. Pin Name I/O Function

– 31 –
Pin No. Pin Name I/O Function
54 NC — Not used for this set (Open)
55 LCD13 O Output of segment signal to the LCD
56 NC — Not used for this set (Open)
57 CE O Output of chip enable control signal
58 RQT I Input of request signal for MB89133LPFV communication
59 NC — Not used for this set (Open)
60 BEEP O Output of beep sound
61 PRE AMP CTL O Preamplifier output switching “ L ”: TC, “ H ”: RADIO
62 DDC (TC) ON O Output of DC-DC converter control signal
63 TC CLK O Communication clock input/output terminal
64 TC DATA I Communication data input/output terminal