Jvc KDS 743 R Service Manual

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KD-S743R/KD-S741R 1-2 (No.49810) 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-S743R/KD-S741R (No.49810)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-S743R/KD-S741R (No.49810)1-31 - Pin function Pin No. Symbol Function 1 VIN1-A CH1 input AMP_inverted input 2 VIN1+A CH1 input AMP_non-inverted input 3 VCCP1 CH1 and CH2 power stage power supply 4 VO1+ Output pin(+)for channel 1 5 VO1- CH1 output pin (-) for channel 1 6 VO2+ Output pin(+)for channel 2 7 VO2- Output pin(-)for channel 2 8 VO3+ Output pin(+)for channel 3 9 VO3- Output pin(-)for channel 3 10 VO4+ Output pin(+)for channel 4 11 VO4- Output pin(-)for channel 4 12 VCCP2 CH3 and CH4 power stage powr supply 13 VIN4 Input pin for channel 4 14 VIN4G Input pin for channel 4(for gain adjustment) 15 VIN3 Input pin for channel 3 16 VIN3G Input pin for channel 3(for gain adjustment) 17 VIN2 Input pin for channel 2 18 VIN2G Input pin for channel 2(for gain adjustment) 19 REGIN External PNP transistor base connection 20 3.3VREG 3.3VREG output pin external PNP transistor,collector connection 21 VCCS Signal system GND 22 VREFIN Reference voltage application pin 23 MUTE Output ON/OFF pin 24 VIN1_SW CH1 input OP AMP_changeover pin 25 S_GND Signal system GND 26 VIN1+B CH1 AMP_B non-inverted input pin 27 VIN1-B CH1 AMP_B inverted input pin 28 VIN1 CH1 input pin input OP_AMP output pin

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KD-S743R/KD-S741R 1-40 (No.49810) 4.10 UPD178078GF-593 (IC701) : System CPU - Pin layout - Pin function 80 ~ 51 1 ~ 3050 ~ 31 81 ~ 100 Pin No. Symbol I/O Function 1 STEERING REMOTE I Steering remote input 2~8 NC - No use 9 VOL-DA I/O VOL IC communication line 10 VOL-CLK O VOL IC communication line 11 NC - No use 12 LCD-DA O LCD driver communication line 13 LCD-CLK O LCD driver communication line 14,15 NC - No use 16 LCD-CE O LCD driver communication line 17 SW2 I CD mech switch 18 PSW I CD mech switch 19~22 NC - Not use 23 KEY0 I Key input 24 KEY1 I Key input 25 KEY2 I Key input 26 LEVEL I Audio level input 27 AVDD - Power supply 28 SM I Signal level meter input 29 SQ I SQ level input 30,31 NC - Not use 32 AVSS - Connect to GND 33 REGCPU - Connect to GND with capacitor 34 VDD - Power supply 35 REGOSC I Connect to GND with capacitor 36 X2 - System clock 37 X1 I System clock 38 GND0 - Connect to GND 39 SD/ST I Station detector & Stereo indicator 40 GND2 - Connect to GND 41 NC - No use 42 IFC I IF count input 43 VDDPLL - --- 44 OSC INPUT I FM, AM OSC input 45 NC - No use 46 GNDPLL - --- 47 AM E.OUT O PLL error output for AM 48 FM E.OUT O PLL error output for FM 49 IC(VPP) - Setting to write for flash