Jvc KDS 821 R Service Manual

Page 1

1-2 KD-S821R ! 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. Safety precaution ! Please use enough caution not to see the beam directly or touch it in case of an adjustment or operation check.

Page 2

1-3 KD-S821R Front bracketCD mechanism control board Damper bracket CD mechanism assy FD screw Feed motor assy FD gearPickup unit Preventing static electricity 1.Grounding to prevent damage by 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. 2.About the earth processing for the destruction prevention by static electricity Static electricity in the work area can destroy the optical pickup (laser diode) in devices such as CD players. Be careful to use proper grounding in the area where repairs are being performed. 2-1 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. 2-2 Ground yourself Use an anti-static wrist strap to release any static electricity built up in your body. 3. Handling the optical pickup 1. 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.) 2. 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. 4.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. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it Conductive material (conductive sheet) or iron plate (caption) Anti-static wrist strap Soldering Attention when traverse unit is decomposed 1.Solder is put up before the card wire is removed from connector on the CD substrate as shown in Figure. (When the wire is removed without putting up solder, the CD pick-up assembly might destroy.) 2.Please remove solder after connecting the card wire with when you install picking up in the substrate.*Please refer to "Disassembly method" in the text for pick-up and how to detach the substrate.

Page 6

1-7 KD-S821R Prior to performing the following procedure, remove the front panel assembly. Remove the four screws G attaching the rear cover on the back of the front panel assembly. Unjoint the twelve joints c with the front panel and the rear cover. Remove the control switch board on the back of the front panel. 1. 2. 3. Removing the control switch board (See Fig.10 to 12) Fig.10 Fig.11 Fig.12 G GG G Rear cover Front panel Control switch board Joints c Joints c Front panel Rear cover Joints c Joints c

Page 28

1-29 KD-S821R 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1632 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 SDA GND OUTLR OUTLF TL B2L B1L IVL ILL QSL INCDCHL IMD INTUL INCDLSCL VCC OUTRR OUTRF TR B2R B1R IVR ILR QSR Vref INCDCHR CAP INTUR INCDR CD-CH TAPE TUNER POWER SUPPLY SOURCE SELECTORVOLUME 1 +20 to -31 dB LOUDNESS LEFTBASS LEFT +15 dBTREBLE LEFT +12 dB BASS RIGHT +15 dBTREBLE RIGHT +12 dBMUTE FUNCTION ZERO CROSS DETECTORVOLUME 2 0 to 55 dB BALANCE FENDER REAR VOLUME 2 0 to 55 dB BALANCE FENDER FRONT HC BUS REC VOLUME 2 0 to -55dB BALANCE FENDER FRONT VOLUME 2 0 to -55dB BALANCE FENDER REAR VOLUME 1 +20 to -31 dB LOUDNESS RIGHT LOGIC 21 31 2 19 16 15 13 11 22 20 18 1714 23 25 24 26 27 283029 1 323 4 10 8 9 7 65 12 1.Pin layout 3.Pin functions2.Block diagram 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Pin No.Pin No. 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 SDA GND OUTLR OUTLF TL B2L B1L IVL ILL QSL INCDCHL IMO INTUL INCDLSerial data input/output. Ground. output left rear. output left front. Treble control capacitor left channel or input from an external equalizer. Bass control capacitor left channel or output to an external equalizer. Bass control capacitor left channel. Input volume 1. left control part. Input loudness. left control part. Output source selector. left channel. Not used Not used Input C left source. Not used Input B left source. Input A left source. I/O - O O I - - I I O - - I - I I Symbol I/O Symbol I/O Input A right source. Input B right source. Electronic filtering for supply. Input C right source. Reference voltage (0.5Vcc) Not used Output source selector right channel. Input loudness right channel. Input volume 1. right control part. Bass control capacitor right channel Bass control capacitor right channel or output to an external equalizer. Treble control capacitor right channel or input from an external equalizer. Output right front. Output right rear. Supply voltage. Serial clock input. I I - I - - O I I - O I O O - I INCDR INTUR CAP INCDCHR Vref QSR ILR IVR B1R B2R TR OUTRF OUTRR Vcc SCL Functions Functions TEA6320T-X (IC161) : E.volume