SONY WM EX422 Service Manual

WM-EX422

SERVICE MANUAL

Ver 1.1 2003.12

Model Name Using Similar Mechanism NEW MD Mechanism Type MF-WMFX495-147

SPECIFICATIONS

E Model

• Frequency response

Playback: 30 - 18 000 Hz

• Output

Headphones (i) jack Load impedance 8 - 300 Ω

• Power requirements

1.5V DC, battery R6 (AA) x 1

• Dimensions (w/h/d)

Approx. 111.2 x 81.1 x 29.5 mm (4 1⁄2 x 3 1⁄4 x1 3⁄16 in.), excl. projecting parts and controls

• Mass

Approx. 124 g (4.4 oz) (main unit only)

• Supplied accessories

Stereo headphones or earphones (1) Hand strap (1) (European model only) Carrying pouch (1) (Asian model only)

Design and specifications are subject to change without notice.

Battery life* (approximate hours)

Sony alkaline LR6 (SG)** Sony R6P (SR)

Tape playback 35 9

* Measured value by the standard of JEITA (Japan Electronics and

Information Technology Industries Association). (Using a Sony HF series cassette tape)

**When using a Sony LR6(SG) “STAMINA” alkaline dry battery

(produced in Japan).

Note

• The battery life may be shorter depending on the operating condition, the surrounding temperature and battery type.

9-877-095-02

CASSETTE PLAYER

Sony Corporation

Personal Audio Company Published by Sony Engineering Corporation

WM-EX422

TABLE OF CONTENTS

Specifications ........................................................................... 1

1. SERVICING NOTE ...................................................... 3

2. GENERAL ...................................................................... 4

3. DISASSEMBLY

3-1. Cabinet (Front)Sub Assy ............................................ 5

3-2. Main Board ................................................................. 6

3-3. Mechanism Deck ........................................................ 6

3-4. Cassette Holder Sub Assy........................................... 7

4. ADJUSTMENTS

4-1. Mechanical Adjustments ............................................ 8

4-2. Electrical Adjustments ................................................ 8

5. DIAGRAMS

5-1. Block Diagram ............................................................ 9

5-2. Printed Wiring Boards .............................................. 10

5-3. Schematic Diagram .................................................... 11

5-4. IC Block Diagrams ................................................... 12

6. EXPLODED VIEWS

6-1. Cabinet Section ......................................................... 13

6-2. Mechanism Deck Section

(MF-WMFX495-147) ....................... 14

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.

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.

7. ELECTRICAL PARTS LIST ................................... 15

SECTION 1

SERVICING NOTES

WM-EX422

This set detects the rotation of the idler gear (A) (side S) using the photo reflector (PH751). The PH751 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 MD switch (S601) 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. Therefore, 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) 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) Connect the AF oscillator to the TP52 and the BT401 (BATT– ).

4) Supply 1.5 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 MD switch (S601) are set to the center position. If not, set the preset state as follow.

2) Move the MD switch (S601) 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 MD switch (S601) 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 TP52 and the BT401 (BATT–).

3) Press the [FF] button or [REW] button .

4. PLAY mode

1) Check that the preset state is set.

2) Input the square wave to the TP52 and the BT401 (BATT–).

3) Press the Y button will move the slider (NRA) once towards the side REV and then to the side FWD. Move the MD switch (S601) according to this timing will set the PLAY mode (side FWD). Press the Y button another time for a second and move the MD switch (S601) 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 MD

switch (S601) can be determined from the beep sound.

— MAIN Board (Component Side) — — MAIN Board (Conductor Side) —

PH751

TP52

(PHOTO)

RVS

REW

FWD

S601

(MD CONT)

BT401

battery terminal

AF oscillator

square wave

2 Hz, 2 VdB

2Vp-

battery terminal

connect to themotor (M601)

WM-EX422

SECTION 2

GENERAL

This section is extracted from instruction manual.

To attach the hand strap*

OPEN

HOLD

AVLS

VOL**

MEGA BASS

BATT

Y•DIRECTION***

REW

* Supplied with the European model only. ** There is a tactile dot beside VOL to show the direction to turn up the volume. *** The button has a tactile dot.

DISASSEMBLY

The equipment can be removed using the following procedure.

WM-EX422

SECTION 3

Set

Cabinet (front) sub assy

MAIN boardCabinet center

Cassette holder sub assy

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

3-1. CABINET (FRONT) SUB ASSY

Screw (B 1.7 × 9), tapping

Cabinet center

Claws

Mechanism deck

Cabinet (front) sub ass

Claws

Screw (B 1.7 × 9), tapping

Claws

WM-EX422

3-2. MAIN BOARD

MAIN board

Screw (1.7 × 2.5), tapping

Unsolder leads from moto

(four places)

Unsolder HEAD flexible board

3-3. MECHANISM DECK

Claws

Mechanism deck

Cabinet (center) assy

Cabinet (center) ass

Claws

+ 12 hidden pages