Sony wm gx 788 service manual
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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 -K eep 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. SAFETY-RELATED COMPONENT WARNING!! COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED 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 PUBLISHED BY SONY. T ABLE OF CONTENTS WM-GX780/GX788 2 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. 1. SERVICE NOTE ··················\ ··················\ ··················\ ········· 3 2. GENERAL ··················\ ··················\ ··················\ ··················\ ·· 5 3. DISASSEMBLY 3-1. Case Block Assy ··················\ ··················\ ··················\ ······· 6 3-2. Button Rec, Button Assy ··················\ ··················\ ············· 7 3-3. Cassette Lid Assy ··················\ ··················\ ··················\ ······ 7 3-4. Ornament Block Assy Reel, Flexible Retainer ··············· 8 3-5. MAIN Board, Belt (F0) ··················\ ··················\ ·············· 8 3-6. Motor (M901) ··················\ ··················\ ··················\ ··········· 9 3-7. Bracket (cassette) Assy, Holder (FA) Assy ··················\ ··· 9 3-8. Pinch Lever (RA) Assy, Pinch Lever (NA) Assy ·········· 10 3-9. Magnetic Head (HP901) ··················\ ··················\ ··········· 10 4. MECHANICAL ADJUSTMENT ··················\ ·············· 11 5. ELECTRICAL ADJUSTMENT ··················\ ················ 11 6. DIAGRAMS ··················\ ··················\ ··················\ ················ 12 6-1. Block Diagram ··················\ ··················\ ··················\ ········ 13 6-2. Printed Wiring Board (Side A) ··················\ ··················\ ·· 14 6-3. Printed Wiring Board (Side B) ··················\ ··················\ ·· 15 6-4. Schematic Diagram (1/2) ··················\ ··················\ ·········· 16 6-5. Schematic Diagram (2/2) ··················\ ··················\ ·········· 17 6-6. IC Block Diagrams ··················\ ··················\ ··················\ · 18 6-7. IC Pin Function Discription ··················\ ··················\ ······ 19 7. EXPLODED VIEWS 7-1. Case Section ··················\ ··················\ ··················\ ············ 21 7-2. Main Section ··················\ ··················\ ··················\ ··········· 22 7-3. Mechanism Deck Section (MF-WMGX788-162) ········ 23 8. ELECTRICAL PARTS LIST ··················\ ··················\ ··· 24
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WM-GX780/GX788 3 SECTION 1 SERVICE NOTE [Service Mode] The service mode enables to operate the mechanism of WM-GX780/ GX788 while the MAIN board is opened. Rotation of the idler gear (A) (S side) is detected using the photo- reflector (PH701) in the WM-GX780/GX788. PH701 is located on the MAIN board, therefore the rotation of the idler gear (A) (S side) cannot be detected by PH701 when the MAIN board is removed. As a result, the motor cannot be controlled and cannot run correctly. To repair the machine after the MAIN board is removed while the main power is turned on, follow the procedures as described below. 1. Setting 1)Remove the cabinets referring to section 3. DISASSEMBLY. Open the MAIN board. 2) Connect the motor (M601) and the plunger solenoid (PM901) to the MAIN board using the jumper wires. When the extension jig (1-769-143-11) (10 wires as a set) is used, they can be connected easily. 3) Short the TAPE DETECT switch (S303), REV TUME switch (S503), FWD TUME switch (S502) and ATS switch (S302). 4) Connect an AF oscillator to resistor (R712). 5) Connect DC 1.3 V from external regulated power supply to and terminals of the battery. 2. PRE-SET status The PLAY, FF and REW modes can be entered only from the PRE- SET status. 1) Check that the slider (NR) is in the center position (S801), and the FWD/REV switch is also in the center position. When these switches are not in the center position, set them to the PRE-SET status as follows. 2) Move the FWD/REV switch (S801) to the same position as the slider (NR) is set. 3) The slider (NR) can be moved when the main power of the regulated power supply is turned OFF once then back ON. Move the FWD/REV switch (S801) to the center position in synchronism with the timing when the slider (NR) is moved.3. FF, REW modes 1) Check that the PRE-SET status is set. 2) Connect square wave or sine wave to resistor (R712). (See illustration below.) 3) Press the x switch (S703) to enter the STOP mode. 4)Press the FF PRESET+ switch (S708) and the REW PRESET– switch (S707). 4. PLAY mode 1) Check that the PRE-SET status is set. 2) Connect square wave or sine wave to resistor (R712). (See illustration below.) 3) Press the x switch (S703) to enter the STOP mode. 4) When the nNREPEAT switch (S709) of the MAIN board is pressed, the slider (NR) moves once to the F side then moves to the R side. When the FWD/REV switch (S801) is pressed in the synchronism with the above timing, the machine can enter the PLAY (R side) mode. Press the nNREPEAT switch (S709) again, and move the FWD/REV switch (S801) in the synchronism with the motion of slider (NR). It enables the machine to enter into the PLAY (F side) mode. Note 1: When you fail to enter the PLAY mode, re-start from step 1) PRE-SET status. Note 2: Regarding the nNREPEAT (S709), x (S703), FF PRESET+ (S708), and REW PRESET– (S707) switches, use these switches of the remote control unit as much as possible. Note 3: If a headphones are used, the beep sound shows the timing of the FWD/REV switch (S801). – MAIN BOARD (SIDE B) - ENTER (S702)REC (S710) RADIO ON/ BAND (S704) MENU (S706)R710 (Side A) SET (S705) (S801) FWD ←STOP →REV Battery terminal # Battery terminal 3 Sine wave 10 Hz, -3.5 dB OSC Plunger (PM901) Short Short TAPE DETECT SWITCH (S303) REV TUME SWITCH (S503) Y REPEAT (S709) FF/PRESET+ (S708) REW/PRESET– (S707) xRADIO OFF (S703) FWD TUME SWITCH (S502) ATS SWITCH (S302) M601 M