Sony Walkman WM-EX678 Service Manual
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SERVICE MANUAL
Ver 1.0 1999 . 01
Manufactured under license from Dolby Laboratories
Licensing Corporation.
"DOLBY" and the double-D symbol a are trademarks
of Dolby Laboratories Licensing Corporation.
Tape section
Frequency response
(Dolby NR off)
Playback : 30 – 18,000 Hz
Headphones (REMOTE 2 jack)
Output
Load impedance 8 – 300 Ω
General
Power requirements
1.5 V
One rechargeable battery or one R6 (size AA)
battery
Approx. 77.7 × 109.1 × 21.4 mm
Dimensions (w/h/d)
(3
1
/
8
projecting parts and controls
MICROFILM
SPECIFICATIONS
× 4
×
3
/
27
/
inches), incl.
8
32
WM-EX678
Model Name Using Similar Mechanism
Tape Transport Mechanism Type
Mass
Approx. 140 g (5.0 oz.)
Approx. 205 g (7.3 oz)
(incl. rechargeable battery and cassette)
Supplied accessories
Battery case (1)
Stereo earphones with remote control (1)
Battery charger (1)
Rechargeable battery
(NC-6WM, 1.2 V, 600 mAh, Ni-Cd) (1)
Rechageable battery carrying case (1)
Carrying pouch (1)
Design and specification subject to change without notice.
CASSETTE PLAYER
AEP Model
UK Model
NEW
MT-WMEX672-162

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Summary of Contents for Sony Walkman WM-EX678

  • Page 1 WM-EX678 SERVICE MANUAL AEP Model UK Model Ver 1.0 1999 . 01 Manufactured under license from Dolby Laboratories Model Name Using Similar Mechanism Licensing Corporation. Tape Transport Mechanism Type MT-WMEX672-162 “DOLBY” and the double-D symbol a are trademarks of Dolby Laboratories Licensing Corporation.
  • Page 2: Table Of Contents

    LIST ARE CRITICAL TO SAFE OPERATION. REPLACE THESE circuit board (within 3 times). COMPONENTS WITH SONY PARTS WHOSE PART NUMBERS • Be careful not to apply force on the conductor when soldering APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS or unsoldering.
  • Page 3: Service Note

    SECTION 1 SERVISE NOTE [Service Mode] The service mode enables to operate the mechanism of WM-EX678 3. FF, REW modes while the MAIN board is opened. Check that the PRE-SET status is set. Rotation of the idler gear (A) (S side) is detected using the photo- Connect square wave or sine wave to TP53 (P.
  • Page 4 [ Slider (NR) ] [ Tape drive mechanism ] Tape drive mechanism in PLAY mode Gear (NR) (FWD : Left side REV : Right side) Idler Gear Idler Gear (A)(S side) Slider (NR) (A)(T side) Gear Gear (REEL)(S side) (REEL)(T side) Motor Pulley Cam Gear F side R side...
  • Page 5: General

    SECTION 2 This section is extracted from instruction manual. GENERAL — 5 —...
  • Page 6: Disassembly

    SECTION 3 DISASSEMBLY Note : Follow the disassembly procedure as shown in the flow chart below. Case block Motor (F2) (M901) Main board Belt (F2) assembly Magnetic head Reel ornament Pinch lever (N/R) Cassette lid Holder (HP901) assembly assembly assembly assembly Note : Follow the disassembly procedure in the numerical order given.
  • Page 7: Main Board

    3-2. MAIN BOARD 2 Remove soldering (four points) from the leaf switch. 3 Remove soldering (two points) S701 from plunger solenoid. 5 Two screws (M1.4) 1 Remove soldering (six points) from the head flexible boards. 7 MAIN board Note : Be careful of the claw. 6 Screw (M1.4) 4 Remove soldering...
  • Page 8: Motor (F2) (M901)

    3-4. MOTOR (F2) (M901) 1 Two screws (M1.4) 2 Motor (F2) (M901) 3-5. CASSETTE LID ASSEMBLY 1 Screw (M1.4 × 2) 5 Cassette Lid Assembly 2 Two screws (M1.4 × 2) 3 Open the cassette lid. 4 Shaft — 9 —...
  • Page 9: Reel Ornament Assembly

    3-6. REEL ORNAMENT ASSEMBLY 1 Reel Ornamene Assembly Claw Note : Remove the assembly while removing the 5 claws and the boss carefully. Claw Boss Claw Claw Claw 3-7. HOLDER ASSEMBLY 2 Shaft 7 Cassette Bracket Assembly 5 Lock Lever (S) 3 Lock Lever (B) 4 Screw (Toothed Lock) (M1.4)
  • Page 10: Pinch Lever (N)/(R) Assembly

    3-8. PINCH LEVER (N)/(R) ASSEMBLY Claw 1 Remove the pinch lever (R) assembly in the direction of the arrow. Note : Be careful of the claw. 2 Remove the pinch lever (N) assembly in the direction of the arrow. Note : Be careful of the claw. Claw 3-9.
  • Page 11: Mechanical Adjustment

    SECTION 4 SECTION 5 MECHANICAL ADJUSTMENT ELECTRICAL ADJUSTMENT PRECAUTION PRECAUTION Clean the following parts with a denatured-alcohol-moistened Specified voltage: 1.3 V (DC) swab: Switch position (MENU) playback head pinch roller : OFF rubber belts capstan AVLS : OFF Demagnetize the playback head with a head demagnetizer. BL SKIP : OFF Do not use a magnetized screwdriver for the adjustments.
  • Page 12: Diagrams

    WM-EX678 SECTION 6 DIAGRAMS 6-1. BLOCK DIAGRAM 6-2. IC BLOCK DIAGRAMS • SIGNAL PATH B+ SWITCH RIPPLE FILTER : PLAYBACK DDC B+ BATT B+ Q305 Q301 IC301 TA2123F (EL) AUDIO MASTER AMP R-CH: Same as L-CH IC301 RF OUT BASE...
  • Page 13: Schematac Diagram

    WM-EX678 6-4. SCHEMATIC DIAGRAM 1.3 Vp-p 30.5 µsec 2.8 Vp-p 11 µsec Note on Schematic Diagram: • All capacitors are in µF unless otherwise noted. pF: µµF 50 WV or less are not indicated except for electrolytics and tantalums. •...
  • Page 14: Ic Pin Function

    WM-EX678 SECTION 7 EXPLODED VIEWS 6-5. IC PIN FUNCTION NOTE: • -XX, -X mean standardized parts, so they may • The mechanical parts with no reference number When indicating parts by reference number, • MAIN BOARD IC701 ML63512-119TBZ060 (SYSTEM CONTROL) have some differences from the original one.
  • Page 15: Mechanism Deck Block

    7-2. MECHANISM DECK BLOCK (MT-WMEX672-162) M901 PM901 HP901 Ref. No. Part No. Description Remarks Ref. No. Part No. Description Remarks X-3377-039-1 HOLDER ASSY (/M) 3-029-274-01 RETAINER (F2), MOTOR X-3376-295-1 PINCH LEVER (R) ASSY 3-007-433-01 SHEET (N), REFLECTION 3-029-271-01 SPRING (HD) X-3377-037-1 CHASSIS ASSY (F) (/M) X-3376-294-1 PINCH LEVER (N) ASSY 3-010-274-02 TABLE, REEL...
  • Page 16: Electrical Parts List

    SECTION 8 MAIN ELECTRICAL PARTS LIST NOTE: • Due to standardization, replacements in the • CAPACITORS: • SEMICONDUCTORS parts list may be different from the parts uF: µF In each case, u: µ, for example: specified in the diagrams or the components •...
  • Page 17 MAIN Ref. No. Part No. Description Remarks Ref. No. Part No. Description Remarks < JACK > R211 1-216-827-11 METAL CHIP 3.3K 1/16W R212 1-216-809-11 METAL CHIP 1/16W J301 1-779-867-81 JACK (2 REMOTE) (AEP,UK,EE) R212 1-216-825-11 METAL CHIP 2.2K 1/16W <JUMPER CHIP> (FR) R213 1-216-853-11 METAL CHIP...
  • Page 18 WM-EX678 MAIN Ref. No. Part No. Description Remarks Ref. No. Part No. Description Remarks < VARIABLE RESISTOR > ACCESSORIES *********** RV301 1-225-684-21 RES, VAR, CARBON 30K/30K (VOL) RV601 1-225-254-21 RES, ADJ, CARBON 2.2K (TAPE SPEED) 1-418-021-11 REMOTE CONTROL UNIT (RM-WME21) 1-528-252-21 BATTERY CHARGER (BC-7S)(UK) <...

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