SERVICE MANUAL
Frequency response (Dolby NR off)
Playback: 30 - 18 000 Hz
Output
Headphones (i jack)
Load impedance 8 - 300
Power requirements
1.5 V
One rechargeable battery
Dimensions (w/h/d)
Approx. 77.1
× 108.8 × 20.2 mm
Mass
Approx. 147 g
Supplied accessories
Stereo headphones or earphones with remote control (1)
Battery charging stand (1)
AC power adaptor (1)
Rechargeable battery (NH-14WM (A), 1.2 V, 1 350 mAh
(MIN), Ni-MH) (1)
Rechargeable battery carrying case (1)
Carrying pouch (1)
Design and specifications subject to change without notice.
Battery life (Approx. hours) (in playback)
(JEITA*)
Rechargeable NH-14WM (A)
45
fully charged
* Measured value by the standard of JEITA (Japan Electronics
and Information Technology Industries Association). (Using a
Sony HF series cassette tape)
Note
· The battery life may be shorter depending on the
operating condition and the surrounding
temperature.
Ver 1.0 2001.10
9-873-307-01
Sony Corporation
2001J0500-1
Personal Audio Company
C
2001.10
Published by Sony Engineering Corporation
CASSETTE PLAYER
AEP Model
E Model
Chinese Model
Tourist Model
SPECIFICATIONS
WM-EX921
Manufactured under license from Dolby Laborato-
ries.
"Dolby" and the double-D symbol are trademarks of
Dolby Laboratories.
Model Name Using Similar Mechanism
NEW
Tape Transport Mechanism Type
MT-WMEX921-162
2
WM-EX921
TABLE OF CONTENTS
1.
SERVICING NOTES ............................................... 3
2.
GENERAL ................................................................... 5
3.
DISASSEMBLY
3-1. Disassembly Flow ...........................................................
6
3-2. Case Section ....................................................................
6
3-3. MAIN Board ...................................................................
7
3-4. Belt (F0) ..........................................................................
7
3-5. Motor, DC (Capstan/Reel) (M601) .................................
8
3-6. Lid Assy, Cassette ...........................................................
8
3-7. Ornament (Open) Block Assy .........................................
9
3-8. Holder (FA) Assy ............................................................
9
3-9. "Lever (N2) Assy, Pinch", "Lever (R2) Assy, Pinch" .... 10
3-10. Head, Magnetic (Playback) (HP901) ............................. 10
4.
MECHANICAL ADJUSTMENTS ....................... 11
5.
ELECTRICAL ADJUSTMENTS ......................... 11
6.
DIAGRAMS
6-1. Block Diagram ................................................................ 13
6-2. Note for Printed Wiring Board
and Schematic Diagrams ................................................ 14
6-3. Printed Wiring Board
MAIN Board (Component Side) .............................. 16
6-4. Printed Wiring Board
MAIN Board (Conductor Side) ................................ 17
6-5. Schematic Diagram MAIN Board (1/2) .................. 18
6-6. Schematic Diagram MAIN Board (2/2) .................. 19
6-7. IC Pin Function Description ........................................... 20
7.
EXPLODED VIEWS
7-1. Cassette Lid Assy Section ............................................... 21
7-2. Case Section .................................................................... 22
7-3. MAIN Board Section ...................................................... 23
7-4. Mechanism Deck Section-1 (MT-WMEX921-162) ....... 24
7-5. Mechanism Deck Section-2 (MT-WMEX921-162) ....... 25
7-6. Mechanism Deck Section-3 (MT-WMEX921-162) ....... 26
8.
ELECTRICAL PARTS LIST ............................... 27
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 0 OR DOTTED
LINE WITH MARK 0 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.
Note on the AC power adaptor
Use only the supplied AC power adaptor. Do not use
any other AC power adaptor.
Polarity of
the plug
UNLEADED 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.
3
WM-EX921
SECTION 1
SERVICING NOTES
This set detects the rotation of the idler gear (A) (side S) using the
photo reflector (PH701). The PH701 is mounted on the MAIN
board, therefore the idler gear (A) (side S) cannot be detected with
the MAIN board removed. As a result, the motor (M601) cannot
be controlled, causing malfunction.
Further, the DIRECTION switch (S702) is also mounted on the
MAIN board, and with the board removed, the mechanism posi-
tion cannot be detected and the operation is not changed over.
Therefor, when the voltage check is executed with the MAIN board
removed, follow the procedure provided below.
1. Setting
1) Refer to "3. DISASSEMBLY", and remove the MAIN board.
2) Connect the MAIN board to the motor (M601) and the plunger
(PM701) using jumper wires. These can be connected easily
with the use of the extension tool (Part No. 1-769-143-11) (ten
in one set).
3) Short the lands (BP1) by solder.
4) Connect the AF oscillator to the TP31 (PH-S) and the TP10
(GND).
5) Supply 1.3 V to the battery terminals using the regulated power
supply.
2. Preset state
To set the PLAY, FF, REW modes, the preset state must be set.
1) Check that the slider (NRA) and the DIRECTION switch
(S702) are set to the center position. If not, set the preset state
as follow.
2) Move the DIRECTION switch (S702) to the side, which the
slider (NRA) is facing.
3) The slider (NRA) will move when the regulated power supply
switch is set to OFF once and then set to ON. Move the DI-
RECTION switch (S702) according to this timing and set to
the center position.
3. FF, REW modes
1) Check that the preset state is set.
2) Input the square wave or sine wave to the TP31 (PH-S) and
the TP10 (GND).
3) Move the jog lever (S703) toward [FF] or [REW].
4. PLAY mode
1) Check that the preset state is set.
2) Input the square wave or sine wave to the TP31 (PH-S) and
the TP10 (GND).
3) Press the jog lever (S703) will move the slider (NRA) once
towards the side REV and then to the side FWD. Move the
DIRECTION switch (S702) according to this timing will set
the PLAY mode (side FWD). Press the jog lever (S703) another
time for a second and move the DIRECTION switch (S702)
according to the movement of the slider (NRA) will set the
PLAY mode (side REV).
Note 1: If the above fails, perform from preset again.
Note 2: When using headphones, the timing for move the DIRECTION
switch (S702) can be determined from the beep sound.
+
PUSH Y/ x
r
S703
jog lever
S702
(DIRECTION)
BP
FWD
R
STOP
r
REV
PH701
>
FF
.
REW
MAIN Board (Component Side)
MAIN Board (Conductor Side)
connect to the
plunger (PM701)
TP10 (GND)
TP31 (PH-S)
AF oscillator
square wave
(sine wave)
100 Hz, 3.5 dB
connect to the
motor (M601)
battery
terminal 3
battery terminal #
battery terminal #
4
WM-EX921
Slider (NRA)
Rotation system
Rotation system during PLAY.
Rotation system during FF.
Rotation system during REW.
slider (NRA)
side F side R
center
insert flywheel (N)
insert flywheel (R)
reverse pulley
clutch assy (F)
gear (Y)
cam gear
gear (REEL) (side T)
motor pulley
idler gear (A) (side T)
gear (FR)
(FF: left side)
insert flywheel (N)
insert flywheel (R)
reverse pulley
clutch assy (F)
idler gear (B)
gear (Y)
cam gear
gear (REEL) (side T)
gear (REEL) (side S)
motor pulley
idler gear (A) (side T)
idler gear (A) (side S)
gear (NR)
(FWD : left side/
REV : right side)
insert flywheel (N)
insert flywheel (R)
reverse pulley
clutch assy (F)
gear (Y)
cam gear
gear (REEL)
(side S)
motor pulley
idler gear (A)
(side S)
gear (FR)
(REW: right side)
5
WM-EX921
SECTION 2
GENERAL
This section is extracted from
instruction manual.
A
Jog lever
Levier Jog
Jog-Hebel
Plug in firmly.
Branchez fermement.
Fest einstecken.
FF (+)
REW ()
Y
·x
HOLD
Hold shutter
Cache de
verrouillage
Schutzschieber
Jog lever
Levier Jog
Jog-Hebel
C
B
Preparations
Rechargeable Battery A
1 Insert the supplied rechargeable battery NH-14WM
(A) into the rechargeable battery compartment with
correct polarity.
2 Connect the supplied AC power adaptor to the
charging stand, plug in the AC power adaptor to
the house current (mains).
3 Place the main unit on the charging stand.
The CHARGE lamp will light up.
About 30 minutes of charging will charge the
battery to last about 3 hours.
Full charging takes about 6 hours.
The CHARGE lamp will go off when charging is
complete.
You can charge the battery about 300 times.
Note
· Do not use the unit while charging. Remove the unit
from the charging stand when using it.
If you operate the unit while charging, the battery
will not be charged.
If you operate the unit while charging, it may cause
malfunction.
Do not place the unit on the charging stand without
the rechargeable battery. Otherwise, it may cause
malfunction.
When to charge the battery B
Charge the battery when "e" flashes in the display.
Note
· After the battery is replaced, the setting of the SOUND
and MODE buttons will be erased.
Playing a Tape C
1 Insert a cassette and if the HOLD function of
the remote control is on, slide the HOLD
switch in the opposite direction of the arrow
to unlock the controls.
2 Press Y(play)·x(stop) on the remote
control* and adjust the volume with VOL.
Notes on volume control
· The VOL switch on the main unit** has three steps.
Generally, set it to the center and make fine volume
adjustments on the remote control. Set it to the
maximum when the recording level is low. If set to
AVLS (minimum), AVLS is activated (see "Protecting
Your Hearing --AVLS").
· The sound cannot be turned down all the way.
* The Y·x button on the remote control has a tactile
dot.
** There is a tactile dot beside the VOL switch on the
main unit to show the direction to turn up the
volume.
Note on the cassette holder
When opening the cassette holder, make sure the tape is
stopped, then slide the OPEN switch.
If the cassette holder is opened when the tape is running,
the tape may loosen and be damaged.
To
Switch playback to
the other side
Stop playback
Fast forward*
Rewind*
Play the other side from
the beginning (Skip
Reverse function)
Play the same side from
the beginning (Rewind
Auto Play function)
* If Y
·x on the remote control is pressed during fast
forward or rewind, the Walkman switches to playback.
Other Tape Operations
To play the next track/succeeding 9 tracks
from the beginning (AMS*)
On the remote control: Press FF once/repeatedly
during playback.
On the main unit: Move the jog lever toward .FF
once/repeatedly during playback.
To play the current track/previous 8 tracks
from the beginning (AMS*)
On the remote control: Press REW once/repeatedly
during playback.
On the main unit: Move the jog lever toward
>
REW once/repeatedly during playback.
* Automatic Music Sensor
Repeating the current track (repeat single
track function)
On the remote control: Press Y·x twice during
playback ("REP" lights up).
On the main unit: Press the jog lever twice during
playback.
To stop a single repeat
Press Y·x or the jog lever once.
Fast forward/rewind while listening to the
sound (CUE/REVIEW)
On the remote control: Press and hold FF/REW
during playback and release it at the point you want.
On the main unit: Move and hold the jog lever
toward .FF/>REW during playback and
release it at the point you want.
Press
Y·x for more than a
second during playback
Y·x once during
playback
FF during stop
REW during stop
FF for 2 seconds or more
during stop
REW for 2 seconds or more
during stop
REV
FWD
FF
REW
CHARGE
D
SOUND
HOLD
Hold shutter
Cache de
verrouillage
Schutzschieber
MODE
Using Other Functions
Adjusting Playback Mode D
You can adjust the playback direction mode (s or
d) as well as the BL SKIP mode (on or off).
1 Press MODE repeatedly. With each press the
indications change as follows:
s
v
s BL SKIP
v
d
v
d BL SKIP
·When "BL SKIP" is displayed, the tape is fast-
forwarded to the next track if there is a blank space
of longer than 12 seconds. You will hear repeated
sets of three short beeps when skipping a blank.
·When "s" is displayed, both sides of the tape is
played repeatedly.
·When "d" is displayed, both sides of the tape is
played once (if you start from R (REV) side, only
REV side will be played).
Note
· You cannot adjust the playback mode during fast-
forward or rewind.
Playing a Tape Recorded with the
Dolby* B NR System D
Hold down SOUND until ";" appears in the
display.
To cancel Dolby B NR, hold down SOUND again
until ";" disappears.
Note
· You cannot turn on/off the Dolby B NR function
during fast-forward or rewind.
Emphasizing Sound D
1 Press SOUND repeatedly. With each press, the
indications change as follows:
RV (Sound Revitalizer): emphasizes treble sound
MB (Mega Bass): emphasizes bass sound
(moderate effect)
GRV (Groove): emphasizes bass sound (strong
effect)
none: normal (no effect)
Notes
· If the sound is distorted with the mode "GRV", turn
down the volume of the main unit or select other
modes.
· You cannot change the mode during fast-forward or
rewind.
Protecting Your Hearing -- AVLS
(Automatic Volume Limiter System)
D
1 Set the VOL switch on the main unit to AVLS.
To cancel the AVLS function
Set the VOL switch of the main unit to the center or
maximum.
Locking the Controls -- HOLD
Function D
On the remote control, slide the HOLD switch in the
direction of the arrow to lock the controls.
On the main unit, close the hold shutter so that the
jog lever becomes hidden.
B
Operation on the main unit
You can operate the tape with the jog lever on the
main unit. If the jog lever is hidden (i.e., on hold),
slide hold shutter in the direction of "V" to release
hold.
To
Play back
Switch playback to
the other side
Stop playback
Fast forward*
Rewind*
Play the other side from
the beginning (Skip
Reverse function)
Play the same side from
the beginning (Rewind
Auto Play function)
* If the jog lever on the main unit is pressed during fast
forward or rewind, the Walkman switches to playback.
Jog lever
Press once.
Press for more than a
second during playback.
Press once.
Move toward .FF once
during stop.
Move toward >REW
once during stop.
Move and hold toward
.
FF for 2 seconds or
more during stop.
Move and hold toward
>
REW for 2 seconds or
more during stop.