Sony WM-EX921 Service Manual
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Sony WM-EX921 Service Manual

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SERVICE MANUAL
Ver 1.0 2001.10
Manufactured under license from Dolby Laborato-
ries.
"Dolby" and the double-D symbol are trademarks of
Dolby Laboratories.
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.
Sony Corporation
9-873-307-01
2001J0500-1
Personal Audio Company
C 2001.10
Published by Sony Engineering Corporation
WM-EX921
Model Name Using Similar Mechanism
Tape Transport Mechanism Type
SPECIFICATIONS
Battery life (Approx. hours) (in playback)
Rechargeable NH-14WM (A)
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.
AEP Model
E Model
Chinese Model
Tourist Model
NEW
MT-WMEX921-162
(JEITA*)
45
CASSETTE PLAYER

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  • Page 1 Load impedance 8 - 300 Ω * Measured value by the standard of JEITA (Japan Electronics Power requirements and Information Technology Industries Association). (Using a 1.5 V Sony HF series cassette tape) One rechargeable battery Dimensions (w/h/d) Note Approx. 77.1 × 108.8 × 20.2 mm •...

  • Page 2: Table Of Contents

    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.

  • Page 3: Servicing Notes

    WM-EX921 SECTION 1 SERVICING NOTES This set detects the rotation of the idler gear (A) (side S) using the 3. FF, REW modes photo reflector (PH701). The PH701 is mounted on the MAIN 1) Check that the preset state is set.
  • Page 4 WM-EX921 Slider (NRA) Rotation system Rotation system during PLAY. gear (NR) (FWD : left side/ REV : right side) idler gear (A) (side S) idler gear (A) (side T) gear (REEL) (side S) gear (REEL) (side T) motor pulley slider (NRA)

  • Page 5: General

    WM-EX921 SECTION 2 This section is extracted from instruction manual. GENERAL Other Tape Operations Preparations To play the next track/succeeding 9 tracks from the beginning (AMS*) Rechargeable Battery On the remote control: Press FF once/repeatedly 1 Insert the supplied rechargeable battery NH-14WM during playback.

  • Page 6: Disassembly

    WM-EX921 SECTION 3 DISASSEMBLY • This set can be disassembled in the order shown below. 3-1. DISASSEMBLY FLOW 3-2. Case Section 3-3. Main Board 3-4. Belt (F0) 3-5. Motor, DC (Capstan/Reel) (M601) 3-6. Lid Assy, Cassette 3-7. Ornament (Open) Block Assy 3-8.

  • Page 7: Main Board

    WM-EX921 3-3. MAIN BOARD 1 Remove seven solders of “motor, DC (M601)”. 2 screw 2 screw (M1.4) (toothed lock) S702 3 MAIN board 1 Remove six solders of head flexible board. 2 screw 1 Remove two solders of “solenoid, plunger”.

  • Page 8: Motor, Dc (Capstan/Reel) (M601)

    WM-EX921 3-5. MOTOR, DC (CAPSTAN/REEL) (M601) 1 two screws (M1.4) 2 motor, DC (capstan/reel) (M601) 3-6. LID ASSY, CASSETTE 2 two screws (M1.4) 4 lid assy, cassette 2 screw (M1.4) 3 boss 1 Open “lid assy, cassette”.

  • Page 9: Ornament (Open) Block Assy

    WM-EX921 3-7. ORNAMENT (OPEN) BLOCK ASSY 2 claw 4 two claws 5 ornament (open) block assy 3 boss 3-8. HOLDER (FA) ASSY 4 screws (M1.4) 5 lever (S) (/M), lock 7 bracket (cassette/910) assy 8 Remove six solders of head flexible board.

  • Page 10: Lever (N2) Assy, Pinch", "Lever (R2) Assy, Pinch

    WM-EX921 3-9. “LEVER (N2) ASSY, PINCH”, “LEVER (R2) ASSY, PINCH” 1 claw 2 Remove “lever (R2) assy, pinch” in the direction of the arrow. 3 claw 4 Remove “lever (N2) assy, pinch” holder (FA) assy in the direction of the arrow.

  • Page 11: Mechanical Adjustments

    WM-EX921 SECTION 4 SECTION 5 MECHANICAL ADJUSTMENTS ELECTRICAL ADJUSTMENTS Precaution Precaution 1. Clean the following parts with a denatured-alcohol-moistened 1. Specified voltage : 1.3 V (DC) swab: 2. Switch position playback head pinch roller VOL/AVLS switch : Center (NOR) rubber belts capstan 3.
  • Page 12 WM-EX921 MEMO...

  • Page 13: Diagrams

    WM-EX921 SECTION 6 DIAGRAMS 6-1. BLOCK DIAGRAM RIPPLE FILTER BATT B+ Q309 J301 AUDIO MASTER AMP AUDIO MASTER AMP IC301 (1/2) IC301 (2/2) HP901 (PLAYBACK) (HEADPHONE WITH REMOTE CONTROL) IN-L POWER AMP PRE OUT L-CH OUT-L IN-L PREAMP CONTROL OUT-L...

  • Page 14: Note For Printed Wiring Board And Schematic Diagrams

    WM-EX921 6-2. NOTE FOR PRINTED WIRING BOARD AND SCHEMATIC DIAGRAMS • Waveforms Note on Printed Wiring Board: Note on Schematic Diagram: 1 IC705 wh (CB2) 6 IC601 4 (UIN), 5 (VIN), 6 (WIN) • All capacitors are in µF unless otherwise noted. pF: µµF •...
  • Page 15 WM-EX921 • IC Block Diagrams IC301 TA2123AF (EL) IC601 LB1994M-TLM 36 35 M CENTER – RF IN BUFFER COMPARATOR PW GND – OUT B PW B OUT C C-AMP SW 37 BUFFER MT TC PW A PW C OUT A –...

  • Page 16: Main Board (Component Side)

    WM-EX921 6-3. PRINTED WIRING BOARD – MAIN Board (Component Side) – :Uses unleaded solder. • Semiconductor Location Ref. No. Location D701 D702 IC301 MAIN BOARD IC303 IC601 (COMPONENT SIDE) IC701 IC704 IC705 PH701 S301 IC701 Q305 Q309 AVLS Q311 Q315...

  • Page 17: Main Board (Conductor Side)

    WM-EX921 6-4. PRINTED WIRING BOARD – MAIN Board (Conductor Side) – :Uses unleaded solder. • Semiconductor Location Ref. No. Location Q302 HP901 Q304 (PLAYBACK) Q306 Q312 Q314 L-ch Q317 MAIN BOARD (CONDUCTOR SIDE) R-ch L-ch R-ch (CHASSIS) TP10 (GND) M601...

  • Page 18: Schematic Diagram - Main Board (1/2)

    WM-EX921 6-5. SCHEMATIC DIAGRAM – MAIN Board (1/2) – • • See page 14 for Waveforms. See page 15 for IC Block Diagrams. (Page 19) The components identified by mark 0 or dotted line with mark 0 are critical for safety.

  • Page 19: Schematic Diagram - Main Board (2/2)

    WM-EX921 6-6. SCHEMATIC DIAGRAM – MAIN Board (2/2) – • See page 15 for IC Block Diagrams. (Page 18) The components identified by mark 0 or dotted line with mark 0 are critical for safety. Replace only with part number specified.

  • Page 20: Ic Pin Function Description

    WM-EX921 6-7. IC PIN FUNCTION DESCRIPTION • IC705 ML63514-025TBZ060 (SYSTEM CONTROLLER) Pin No. Pin Name Description Pin No. Pin Name Description P-SIG P-SIG signal input from the capstan/reel motor driver IC (IC601) AUDIO ATT Audio attenuate control signal output It attenuates, when cue/review “H”: attenuate FWD SW Tape direction switch (S702) input terminal “L”: forward position...

  • Page 21: Exploded Views

    WM-EX921 SECTION 7 EXPLODED VIEWS NOTE: • -XX and -X mean standardized parts, so they • Items marked “*” are not stocked since they • Abbreviation may have some difference from the original are seldom required for routine service. Some CH : Chinese model one.

  • Page 22: Case Section

    WM-EX921 7-2. CASE SECTION not supplied Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark 3-233-765-01 CAP 3-233-761-21 CASE (RED) 3-237-316-01 SCREW 3-704-197-32 SCREW (M1.4X3.0) 3-233-767-01 SHUTTER (B) 3-233-773-01 KNOB (VOL) (SILVER) 3-233-766-01 SHUTTER (A) 3-233-773-11 KNOB (VOL) (BLUE)

  • Page 23: Main Board Section

    WM-EX921 7-3. MAIN BOARD SECTION MT-WMEX921-162 S704 not supplied Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark 3-038-056-01 TERMINAL BOARD (MINUS) (/M) 3-236-616-11 COVER, MD (AEP, EE, FR) 3-375-114-41 SCREW 3-236-616-21 COVER, MD (CH, KR) 3-224-837-01 SHEET (ATS) 3-365-630-41 SCREW (M1.4)

  • Page 24: Mechanism Deck Section-1 (Mt-Wmex921-162)

    WM-EX921 7-4. MECHANISM DECK SECTION-1 (MT-WMEX921-162) PM701 mechanism deck section-2 Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark 3-010-274-02 TABLE, REEL 3-029-281-01 GEAR, IDLER (B) 3-010-954-01 SPRING (BT), COMPRESSION 3-040-897-04 SPRING (TGA), TORSION X-3376-813-1 CLUTCH ASSY (F)

  • Page 25: Mechanism Deck Section-2 (Mt-Wmex921-162)

    WM-EX921 7-5. MECHANISM DECK SECTION-2 (MT-WMEX921-162) M601 mechanism deck section-3 Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark 3-029-276-02 WASHER (STOPPER R) 3-007-428-01 WASHER (R) 3-029-289-01 WASHER 3-029-268-21 FLYWHEEL (R), INSERT 3-029-275-01 WASHER (STOPPER N) 3-029-765-01 SCREW (M1.4), TOOTHED LOCK...

  • Page 26: Mechanism Deck Section-3 (Mt-Wmex921-162)

    WM-EX921 7-6. MECHANISM DECK SECTION-3 (MT-WMEX921-162) HP901 Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark 3-046-789-01 SPRING (HDA) X-3377-589-1 HOLDER (FA) ASSY 3-033-757-01 SHEET (H) X-3377-995-2 LEVER (R2) ASSY, PINCH X-3377-994-2 LEVER (N2) ASSY, PINCH HP901...

  • Page 27: Electrical Parts List

    WM-EX921 SECTION 8 ELECTRICAL PARTS LIST MAIN NOTE: • Due to standardization, replacements in the • Items marked “*” are not stocked since they The components identified by mark 0 or dotted line with mark parts list may be different from the parts speci- are seldom required for routine service.
  • Page 28 WM-EX921 MAIN Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark < IC > R115 1-218-961-11 RES-CHIP 4.7K 1/16W (FR) IC301 8-759-579-12 IC TA2123AF (EL) R116 1-218-973-11 RES-CHIP 1/16W IC303 8-759-488-80 IC NJM2185AV-TE2 R117 1-208-675-11 METAL CHIP 0.5%...
  • Page 29 WM-EX921 MAIN Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark R611 1-218-983-11 RES-CHIP 330K 1/16W ACCESSORIES R612 1-218-989-11 RES-CHIP 1/16W ************ R613 1-218-989-11 RES-CHIP 1/16W R614 1-218-977-11 RES-CHIP 100K 1/16W 1-475-622-21 ADAPTOR, AC (AC-E455) (CH) R615...

  • Page 30: Revision History

    WM-EX921 REVISION HISTORY Clicking the version allows you to jump to the revised page. Also, clicking the version at the upper right on the revised page allows you to jump to the next revised page. Ver. Date Description of Revision...

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