Sony WMEX-921 Service manual

WM-EX921

SERVICE MANUAL

Ver 1.0 2001.10

Manufactured under license from Dolby Laboratories. “Dolby” and the double-D symbol are tr ademarks of Dolby Laboratories.

SPECIFICATIONS

Frequency response (Dolby NR off)

Playback: 30 - 18 000 Hz

Output

Headphones (i jack) Load impedance 8 - 300 Ω

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.

AEP Model

E Model

Chinese Model

Tourist Model

Model Name Using Similar Mechanism NEW Tape T ransport Mechanism T ype MT-WMEX921-162

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.

9-873-307-01 Sony Corporation

2001J0500-1 Personal Audio Company C 2001.10 Published by Sony Engineering Corporation

CASSETTE PLAYER

WM-EX921

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

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

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.

UNLEADED SOLDER

Boards requiring use of unleaded solder are printed with the leadfree 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.

SAFETY-RELATED COMPONENT WARNING!!

COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED LINE WITH MARK 0 ON THE SCHEMA TIC 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 PUBLISHED BY SONY.

SECTION 1

SERVICING NOTES

WM-EX921

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 position cannot be detected and the operation is not changed over. Therefor, when the voltage check is e xecuted 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 po wer supply.

2. Preset state T o 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 po wer supply switch is set to OFF once and then set to ON. Move the DIRECTION 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 PLA Y mode (side FWD). Pr ess 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.

– MAIN Board (Component Side) – – MAIN Board (Conductor Side) –

PUSH – Y/

S703

jog lever

PH701

REW

S702

(DIRECTION)

FWD

STOP

REV

connect to the

plunger (PM701)

battery terminal

TP31 (PH-S)

TP10 (GND)

AF oscillator

–

square wave

(sine wave)

100 Hz, –3.5 dB

connect to the

motor (M601)

battery terminal

WM-EX921

Slider (NRA) Rotation system

Rotation system during PLAY.

idler gear (A) (side T)

gear (REEL) (side T)

slider (NRA)

cam gear

gear (NR) (FWD : left side/

REV : right side)

idler gear (A) (side S)

gear (REEL) (side S)

motor pulley

side F

side R

center

gear (Y)

insert flywheel (N) insert flywheel (R)

idler gear (B)

Rotation system during FF. Rotation system during REW.

gear (FR) (REW: right side)

idler gear (A) (side T)

gear (REEL) (side T)

cam gear

gear (FR) (FF: left side)

motor pulley

cam gear

clutch assy (F)

idler gear (A) (side S)

reverse pulley

gear (REEL) (side S)

motor pulle

clutch assy (F)

gear (Y)

insert flywheel (N) insert flywheel (R)

gear (Y)

reverse pulle

clutch assy (F)

reverse pulley

insert flywheel (N) insert flywheel (R)

SECTION 2

GENERAL

WM-EX921

This section is extracted from instruction manual.

Jog lever Levier Jog Jog-Hebel

Hold shutter Cache de verrouillage Schutzschieber

REV

FWD

Plug in firmly. Branchez fermement. Fest einstecken.

FF (+)

HOLD

Jog lever Levier Jog Jog-Hebel

REW

HOLD

CHARGE

Y•x

REW (–)

SOUND

MODE

Preparations

Rechargeable Battery

1Insert the supplied rechargeable battery NH-14WM

(A) into the rechargeable battery compartment with correct polarity.

2Connect the supplied AC power adaptor to the

charging stand, plug in the AC power adaptor to the house current (mains).

3Place 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

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

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.

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.

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.

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.

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

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.

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.

Using Other Functions

Adjusting Playback Mode

You can adjust the playback direction mode (s or d) as well as the BL SKIP mode (on or off).

1Press MODE repeatedly. With each press the

indications change as follows:

s BL SKIP

d BL SKIP

•When “BL SKIP” is displayed, the tape is fastforwarded 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 fastforward or rewind.

Playing a Tape Recorded with the Dolby* B NR System

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

1Press 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)

1Set 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

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.

WM-EX921

• This set can be disassembled in the order shown below.

3-1. DISASSEMBLY FLOW

SECTION 3

DISASSEMBLY

Set 3-2. Case Section 3-3. Main Board

3-7. Ornament (Open) Block Assy3-6. Lid Assy, Cassette

3-9. “Lever (N2) Assy, Pinch”, “Lever (R2) Assy, Pinch”

Note: Follow the disassembly procedure in the numerical order given.

3-2. CASE SECTION

S301

Note: On installation

“lid assy, cassette” adjust the S301 and knob (vol).

3-4. Belt (F0) 3-5. Motor, DC (Capstan/Reel) (M601)

3-8. Holder (FA) Assy

3-10. Head, Magnetic (Playback) (HP901)

cassette assy, lid

knob (VOL)

two screws (M1.4)

case section

Close terminal board assy.

lid, battery case

two screws (M1.4)

screw (M1.4)

Open “lid, battery case”.

claw

3-3. MAIN BOARD

screw

Remove seven solders of “motor, DC (M601)”.

screw (M1.4) (toothed lock)

S702

MAIN board

Remove four solders of

slider

“switch, leaf (S704)”.

WM-EX921

Remove six solders of head flexible board.

Remove two solders of “solenoid, plunger”.

Note: On installation

MAIN board adjust the S702 and slider.

3-4. BELT (F0)

flywheel (R), insert

belt (F0)

pulley, motor

pulley, reverse

terminal board, battery

belt (F0)

flywheel (N), insert

Remove solder of “terminal board, battery”.

WM-EX921

)

3-5. MOTOR, DC (CAPSTAN/REEL) (M601)

two screws (M1.4)

motor, DC (capstan/reel) (M601

3-6. LID ASSY, CASSETTE

lid assy, cassette

boss

two screws (M1.4)

screw (M1.4)

Open “lid assy, cassette”.

3-7. ORNAMENT (OPEN) BLOCK ASSY

WM-EX921

boss

claw

two claws

ornament (open) block assy

3-8. HOLDER (FA) ASSY

lever (S) (/M), lock

Remove six solders of head flexible board.

screws (M1.4)

bracket (cassette/910) assy

boss

holder (FA) assy

boss

lever (B) (/M), loc

two screws (M1.4)

+ 21 hidden pages

Sony WMEX-921 Service manual

TABLE OF CONTENTS

SERVICING NOTES

GENERAL

3-1. DISASSEMBLY FLOW

DISASSEMBLY

case section

MAIN board

belt (F0)

3-5. MOTOR, DC (CAPSTAN/REEL) (M601)

lid assy, cassette

ornament (open) block assy

holder (FA) assy