JVC KD-SX8250 Service Manual
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JVC KD-SX8250 Service Manual

JVC KD-SX8250 Service Manual

Cd receiver
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See also: Service Manual , Instruction Manual
SERVICE MANUAL
KD-SX8250/KD-SX780
SOUND
U
R
SOURCE
F
D
VOL
VOL
SOUND
U
R
SOURCE
F
D
VOL
VOL
Difference point
SUBWOOFER
LINE-OUT
DIMMER
FINDER
Contents
Safety precaution
Preventing static electricity
Disassembly method
Adjustment method
CD RECEIVER
KD-SX8250
KD-SX780
KD-SX8250
4V
SILVER
1-2
1-3
1-4
1-18
COPYRIGHT
2002 VICTOR COMPANY OF JAPAN, LTD.
7
KD-SX780
2V
J
BLACK
Flow of functional
operation unit TOC read
Maintenance of laser pickup
Replacement of laser pickup
Description of major ICs
KD-SX8250/KD-SX780
COMPACT
DIGITAL AUDIO
Area Suffix
Northern America
1-19
1-21
1-21
1-22
No.49690
Feb. 2002

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Summary of Contents for JVC KD-SX8250

  • Page 1 KD-SX8250/KD-SX780 SERVICE MANUAL CD RECEIVER KD-SX8250/KD-SX780 KD-SX8250 SOUND SOURCE KD-SX780 SOUND SOURCE COMPACT DIGITAL AUDIO Difference point KD-SX8250 KD-SX780 SUBWOOFER LINE-OUT Area Suffix DIMMER Northern America FINDER SILVER BLACK Contents Safety precaution Flow of functional Preventing static electricity operation unit TOC read...

  • Page 2: Safety Precaution

    KD-SX8250/KD-SX780 Safety precaution ! CAUTION 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. ! CAUTION Please use enough caution not to see the beam directly or touch it in case of an...

  • Page 3: Preventing Static Electricity

    KD-SX8250/KD-SX780 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. 1.1. 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.

  • Page 4: Disassembly Method

    KD-SX8250/KD-SX780 Disassembly method Removing the front panel unit (See Fig.1) Press the release switch and remove the front panel unit in the direction of the arrow. Front panel unit Fig.1 Removing the front chassis (See Fig.2 to 4) Remove the two screws A attaching the front chassis.
  • Page 5 KD-SX8250/KD-SX780 Removing the bottom cover (See Fig.6) Joints d Prior to performing the following procedure, remove Bottom cover the front chassis and the heat sink. Turn the body upside down. Insert a screwdriver to the two joints d and two joints...
  • Page 6 KD-SX8250/KD-SX780 Removing the CD mechanism assembly CD mechanism assembly (See Fig.9) Prior to performing the following procedure, remove the front chassis, the heat sink, bottom cover and the main amplifier board assembly. Remove the three screws F attaching the cassette mechanism assembly from the top cover.

  • Page 7: Removing The Top Cover

    KD-SX8250/KD-SX780 Removing the top cover (See Fig.1 and 2) Remove the two screws A on each side of the body. Top cover Joints a Lift the front side of the top cover and move the cover backward to release the two joints a.
  • Page 8 KD-SX8250/KD-SX780 Removing the DET switch (See Fig.3 and 6) Extend the two tabs c of the feed sw. holder and pull out the switch. DET switch Unsolder the DET switch wire if necessary. Connector board Removing the chassis unit (See Fig.7 and 8)
  • Page 9 KD-SX8250/KD-SX780 Removing the clamper assembly (See Fig.9 and 10) Prior to performing the following procedure, remove Clamper arm the top cover. spring Remove the clamper arm spring. Move the clamper assembly in the direction of the arrow to release the two joints d.

  • Page 10: Removing The Pickup Unit

    KD-SX8250/KD-SX780 Feed sw. holder Removing the pickup unit (See Fig.13 to 17) Joint f Prior to performing the following procedure, remove the top cover, the connector board and the chassis unit. Remove the screw D and pull out the pu. shaft holder from the shaft.
  • Page 11 KD-SX8250/KD-SX780 Removing the trigger arm (See Fig.18 and 19) Joint k Prior to performing the following procedure, remove the top cover, the connector board and the clamper unit. Trigger arm Turn the trigger arm in the direction of the arrow to release the joint k and pull out upward.
  • Page 12 KD-SX8250/KD-SX780 Joint a' Link plate Joint r Removing the select arm (L) / select lock Select arm (L) Joint z Select arm (R) arm (See Fig.21 and 22) Select lock arm Prior to performing the following procedure, remove the top plate assembly.
  • Page 13 KD-SX8250/KD-SX780 Link plate Joint r Joint a' Removing the select arm (R) / link plate Select arm (L) Joint z Select arm (R) (See Fig.21 and 22) Select lock arm Prior to performing the following procedure, remove the top plate assembly.
  • Page 14 KD-SX8250/KD-SX780 Roller guide Removing the loading roller assembly Washer (See Fig.27 to 29) Loading roller assembly Prior to performing the following procedure, remove the clamper assembly and the top plate assembly. Roller guide Push inward the loading roller assembly on the gear side and detach it upward from the slot of the joint d’...
  • Page 15 KD-SX8250/KD-SX780 Removing the loading gear (5), (6) and Loading gear bracket (7) (See Fig.31 and 32) Loading gear (6) Prior to performing the following procedure, remove the top cover, the chassis unit and the top plate assembly. Remove the screw J...
  • Page 16 KD-SX8250/KD-SX780 Removing the gears (See Fig.33 to 36) Prior to performing the following procedure, remove the top cover, the chassis unit, the top plate assembly and the pickup unit. Slot j' Pull out the feed gear. Slide plate Loading plate assembly...
  • Page 17 KD-SX8250/KD-SX780 Removing the turn table / spindle motor Turn table (See Fig.37 and 38) Prior to performing the following procedure, remove the top cover, the connector assembly and the chassis / clamper assembly. Remove the two screws K attaching the spindle motor assembly through the slot of the turn table on top of the body.

  • Page 18: Adjustment Method

    Power supply voltage DC 14.4V(11V to 16V allowance) Load impedance 4 (4 to 8 allowance) Line-out Level/Impedance KD-SX8250 : 4.0 V/20k load(full scale) KD-SX780 : 2.0 V/20k load(full scale) Output impedance : 1k How to connect the extension cable for adjusting...

  • Page 19: Flow Of Functional Operation Unit Toc Read

    KD-SX8250/KD-SX780 Flow of functional operation unit TOC read Power ON When the laser diode correctly Set Function CD When the pickup correctly moves emits to the inner area of the disc Microprocessor $82 $81 Microprocessor Disc inserted commands commands 3.3V 3.3V...

  • Page 20: Feed Section

    KD-SX8250/KD-SX780 Feed section Is the voltage output at Is the wiring for IC521 Is 3.3V present at IC561 IC521 pin "40" 5V or 0V? (56)~(64) correct? pin "20"? Check CD 8V Check the vicinity of and 5V. IC521. Is 4V present at both...

  • Page 21: Maintenance Of Laser Pickup

    KD-SX8250/KD-SX780 Maintenance of laser pickup (1) Cleaning the pickup lens Before you replace the pickup,please try to clean the lens with a alcohol soaked cotton swab. (2) Life of the laser diode When the life of the laser diode has expired.

  • Page 22: Description Of Major Ics

    KD-SX8250/KD-SX780 Description of major ICs UPD784215AGC143(IC701):MAIN CPU 1.Pin layout 2.Block diagram RxD1/SI1 INTP2/NMI PROGRAMMABEL UART/IOE1 TxD1/SO1 INTP0,INTP1 INTERRUPT BAUD-RATE ASCK1/SCK1 INTP3-INTP6 CONTROLLER GENERATOR RxD2/SI2 TI00 UART/IOE2 TIMER/COUNTER TxD2/SO2 TI01 BAUD-RATE (16 BITS) ASCK2/SCK2 GENERATOR CLOCKED TIMER/COUNTER1 SERIAL (8 BITS) INTERFACE...
  • Page 23 KD-SX8250/KD-SX780 UPD784215AGC143(1/2) Pin No. Symbol Function Non connected Non connected Detection switch of CD mechanism CD mecha position setting SW Loading motor control signal output MOTOR SEL Loading /feed motor selecting output Non connected ANT CONT Antenna remote output 5V connection Sub-clock 32.738MHz...
  • Page 24 KD-SX8250/KD-SX780 UPD784215AGC143(2/2) Symbol Function Pin No. Non connected Non connected SD/ST Station detector and stereo signal input. It is H and there is a bureau.It is L and a stereo. Non connected MONO Monaural ON/OFF switch output. At the time of the MONO ON :H.
  • Page 25 KD-SX8250/KD-SX780 BA3220FV-X (IC341,IC441) : Line out amp 1.Pin layout 3220 2.Block diagram OUTL OUTR RGND LGND REFR REFL FILTER 1-25...
  • Page 26 KD-SX8250/KD-SX780 HA13164 (IC961) : Regulator 1.Pin layout 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 2.Block diagram Surge Protector BIAS UNIT R: note1) TAB (header of IC) connected to GND 3.Pin function Pin No.
  • Page 27 KD-SX8250/KD-SX780 HD74HC126FP-X (IC771) : Buffer 1.Terminal layout 3.Pin function Input Output Note: H : High L : Low X : H and L Z : H.L.X 2.Block diagram Output Input Output Sample as Load Circuit 1 Output Sample as Load Circuit 1...
  • Page 28 KD-SX8250/KD-SX780 LA47503(IC351):Power amp. 1.Terminal layout Protective circuit Stand by Switch Ripple Mute Filter circuit protective circuit Muting & On Time Control Circuit 1-28...
  • Page 29 KD-SX8250/KD-SX780 2.Terminal layout 3.Pin function LA47503 Pin No. Symbol Function Header of IC AC CONT1 Power GND GND1 Outpur(-) for front Rch OUTFR- Stand by input STBY Output (+) for front Rch OUTFR+ Power input Vcc1/2 Output (-) for rear Rch...
  • Page 30 KD-SX8250/KD-SX780 LA6579H-X(IC561):CD driver 1.Terminal layout VN1_SW [H]:OP-AMP_A [L]:OP-AMP_B Signal system It is ON/OF as for all output H:ON MUTE L:OFF It is ON/OF Power sytem as for all output Power sytem GND Signal system power supply 33vreg(pnptRExternal) 1-30...
  • Page 31 KD-SX8250/KD-SX780 LA6579H Symbol Description VIN1-A CH1 input AMP_A reversing input. VIN1+A CH1 input AMP_A non-reversing input. VCCP1 CH1 and CH2 power steps power supply. VO1+ CH1 output terminal (+) VO1- CH1 output terminal (-) VO2+ CH2 output terminal (+) VO2-...
  • Page 32 KD-SX8250/KD-SX780 LC75344M-X(IC252):Sub woofer 1.Terminal layout 2.Block diagram 3.Pin function Symbol Function Input signal connections LOUT Volume output Power supply Serial data and clock inputs used for IC control Chip enable Data is writen to the internal latch when this pin goes from high to low. The internal analog switches operate at this point.
  • Page 33 KD-SX8250/KD-SX780 LC75412W(IC301):E.VOLUME 1.Terminal layout & block daiagram LVref ZERO CROSSDET Multiplexer LVref CONTROL INTERFACE LOGIC CIRCUITVA CIRCUIT RVref Multiplexer ZERO CROSSDET NO SIGNAL TIMMER RVref 2.Function Symbol Function Pin No. Single end input terminal Differential motion input terminal LSELO Input selector output terminal RSELO Then terminal for roudness.CR for a high region amends is connected for LCT(RCT) and...
  • Page 34 KD-SX8250/KD-SX780 LC75412W Symbol Function Pin No. LF1C1 The capacitor connection terminal of the filter composition for the F1 stap of the equalizer. LF1C2 LF1C1(RF1C1)~LF1C2(RF1C2),Connect the capacitor for LF1C2(RF1C2)~LF1C3(RF1C3). LF1C3 RF1C1 RF1C2 RF1C3 LF3C1 Capacitor connection terminal of filter composition for F3 strap of equalizer.
  • Page 35 KD-SX8250/KD-SX780 LC75873NW(IC601):LCD Driver 1.Pin layout 2.Block diagram VDD1 COMON SEGMENT DRIVER DRIVER VDD2 CLOCK SHIFT REGISTOR GENERATOR ADDRESS DETECTOR 3.Pin function Pin No. Pin name Description Segment outouts for displaying the display data DIMMER,S1 79,80 transferred by serial data input.
  • Page 36 KD-SX8250/KD-SX780 TA2157FN-X(IC501):RF amp 1.Terminal layout 2.Block diagram PEAK 50 A BOTTOM PEAK 1.75k 240k 15pF x0.5 240k 15pF x0.5 180k 40pF RFGC (APC SW) (TE BAL) (AGC Gian) (TE BAL) VCTRLPIN Normal mode APC ON -50% +12dB (0dB) Normal mode...
  • Page 37 KD-SX8250/KD-SX780 3.Pin function TA2175FN-X Pin No. Symbol Function 3.3V power supply pin Main-beam amp input pin Main-beam amp input pin Sub-beam amp input pin Sub-beam amp input pin Monitor photo diode amp input pin Laser diode amp output pin APC circuit ON/OFF control signal, laser diode (LDO) control signal input or bottom/peak detection frequency change pin.
  • Page 38 KD-SX8250/KD-SX780 TB2118F-X (IC21) : PLL 1.Terminal Layout 2.Block diagram Constant power supply voltage Buff. ON/OFF AM CP. Phase OSC circuit Reference Counter Comparator switch FM IN 4-bit Prescaler Swallow counter 12-bit AMIN Programmable counter 20-bit BINARY COUNTER Resistor 1 22-bit...
  • Page 39 KD-SX8250/KD-SX780 TC94A14FA(IC521):DSP&DAC 1.Terminal layout & block daiagram Clock generator 1-bit Servo control Digital equalizer Address automatic circuit adjustment circuit Data CLV servo slicer 16 k Synchronous guarantee decoder Audio out Digital circuit output Micro- controller Sub code interface decoder TMAX 2.Pin function...
  • Page 40 KD-SX8250/KD-SX780 TC94A14FA Symbol Description EFM and PLCK phase difference signal output pin. TMAX TMAX detection result output pin. TMAX Detection Result TMAX Output Longer than fixed period "PV " Within fixed period "HiZ" Shorter than fixed period "AV " LPFN Inverted input pin for PLL LPF amp.
  • Page 41 KD-SX8250/KD-SX780 IC-PST600M/G/-W (IC702) : System reset NJM4565M-WE (IC251) : Ope. amp A OUTPUT A INPUT B OUTPUT B INPUT A INPUT B INPUT RPM7138-V4(IC602):Remote control receiver Limiter Comparator Detection crimp 1-41...
  • Page 42 KD-SX8250/KD-SX780 VICTOR COMPANY OF JAPAN, LIMITED MOBILE ELECTRONICS DIVISION PERSONAL & MOBILE NETWORK BUSINESS UNIT. 10-1,1Chome,Ohwatari-machi,Maebashi-city,371-8543,Japan 200202 (No.49690)

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