Jvc KDS 795 Service Manual

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KD-S795 1-2 (No.49789) SECTION 1 Important Safety Precautions 1.1 Safety Precautions ! Burrs formed during molding may be left over on some parts of the chassis. Therefore, pay attention to such burrs in the case of preforming repair of this system. ! Please use enough caution not to see the beam directly or touch it in case of an adjustment or operation check.

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KD-S795 (No.49789)1-3 1.2 Preventing static electricity Electrostatic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc. is discharged, can destroy the laser diode in the traverse unit (optical pickup). Take care to prevent this when performing repairs. 1.2.1 Grounding to prevent damage by static electricity Static electricity in the work area can destroy the optical pickup (laser diode) in devices such as DVD players. Be careful to use proper grounding in the area where repairs are being performed. (1) Ground the workbench Ground the workbench by laying conductive material (such as a conductive sheet) or an iron plate over it before placing the traverse unit (optical pickup) on it. (2) Ground yourself Use an anti-static wrist strap to release any static electricity built up in your body. (3) Handling the optical pickup - In order to maintain quality during transport and before installation, both sides of the laser diode on the replacement optical pickup are shorted. After replacement, return the shorted parts to their original condition. (Refer to the text.) - Do not use a tester to check the condition of the laser diode in the optical pickup. The tester's internal power source can easily destroy the laser diode. 1.3 Handling the traverse unit (optical pickup) (1) Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit. (2) Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optical pickup. For specific details, refer to the replacement procedure in the text. Remove the anti-static pin when replacing the traverse unit. Be careful not to take too long a time when attaching it to the connector. (3) Handle the flexible cable carefully as it may break when subjected to strong force. (4) I t is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it. 1.4 Attention when traverse unit is decomposed *Please refer to "Disassembly method" in the text for the CD pickup unit. - Apply solder to the short land before the flexible wire is disconnected from the connector on the CD pickup unit. (If the flexible wire is disconnected without applying solder, the CDpickup may be destroyed by static electricity.) - In the assembly, be sure to remove solder from the short land after connecting the flexible wire. 1M (caption) Anti-static wrist strap Conductive material (conductive sheet) or iron plate PickupShort-circuit point (Soldering) Flexible wire Pickup Short-circuit point

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KD-S795 1-14 (No.49789) 2.2.7 Removing the pickup unit (See Figs.14 to 18) - Prior to performing the following procedure, remove the top cover, connector board and chassis unit. (1) Remove the screw D and pull out the pu. shaft holder from the pu. shaft. (2) Remove the screw E attaching the feed sw. holder. (3) Move the part e of the pickup unit upward with the pu. shaft and the feed sw. holder, then release the joint f of the feed sw. holder in the direction of the arrow. The joint g of the pickup unit and the feed rack is released, and the feed sw. holder comes off. (4) Remove the pu. shaft from the pickup unit. (5) Remove the screw F attaching the feed rack to the pickup unit. 2.2.8 Reattaching the pickup unit (See Figs.14 to 17) (1) Reattach the feed rack to the pickup unit using the screw F. (2) Reattach the feed sw. holder to the feed rack while setting the joint g to the slot of the feed rack and setting the part f of the feed rack to the switch of the feed sw. holder correct- ly. (3) As the feed sw. holder is temporarily attached to the pickup unit, set to the gear of the joint g and to the bending part of the chassis (joint h) at a time. CAUTION: Make sure that the part i on the underside of the feed rack is certainly inserted to the slot j of the change lock lever. (4) Reattach the feed sw. holder using the screw E. (5) Reattach the pu. shaft to the pickup unit. Reattach the pu. shaft holder to the pu. shaft using the screw D. Fig.14Fig.15 Fig.16 Fig.17 Fig.18 Feed sw. holder E D Joint g Joint f Part e Pickup unit Pu. shaft holder Pu. shaft Feed sw. holder Part ePickup unit Feed rack Feed sw. holder D E Joint f Pu. shaft holder Pu. shaft Pickup unit Joint h Part i Slot j Joint g F Feed rack Pickup unit Joint f Joint g Feed rackPickup unit Feed sw. holder