Sony wm ex 621 service manual

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TABLE OF CONTENTS 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 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 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. SAFETY-RELATED COMPONENT WARNING!! COMPONENTS IDENTIFIED BY MARK ! OR DOTTED LINE WITH MARK ! 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 PUBLISHED BY SONY. WM-EX621 2 1. SERVICE NOTE ·······························································3 2. GENERAL ··········································································5 3. DISASSEMBLY 3-1. CASE SUB ASSY··························································7 3-2. MAIN BOARD·······························································8 3-3. BELT (F4)·······································································8 3-4. MOTOR (CAPSTAN/REEL) (M901)····························9 3-5. LID ASSY, CASSETTE·················································9 3-6. ORNAMENT, REEL····················································10 3-7. HOLDER (FS) ASSY···················································10 3-8. LEVER (N)/(R) ASSY, PINCH····································11 3-9. HEAD, MAGNETIC (HP901)······································11 4. MECHANICAL ADJUSTMENT ································12 5. ELECTRICAL ADJUSTMENT ··································12 6. DIAGRAMS 6-1. BLOCK DIAGRAM·····················································13 6-2. NOTE FOR PRINTED WIRING BOARDS AND SCHEMATIC DIAGRAMS··········································14 6-3. IC BLOCK DIAGRAMS··············································14 6-4. SCHEMATAC DIAGRAM – MAIN BOARD – ··········15 6-5. PRINTED WIRING BOARD – MAIN BOARD – ······16 6-6. IC PIN FUNCTION······················································17 7. EXPLODED VIEWS 7-1. CABINET BLOCK·······················································19 7-2. MAIN BOARD BLOCK··············································20 7-3. MACHANISM BLOCK – 1·········································21 7-4. MACHANISM BLOCK – 2·········································22 8. ELECTRICAL PARTS LIST ·······································23