LG TCH-800, Service Manual

Page 1: ...ON 2 ELECTRICAL ELECTRICAL TROUBLESHOOTING GUIDE 2 1 INTERNAL BLOCK DIAGRAM of ICs 2 7 BLOCK DIAGRAM 2 23 MAIN SCHEMATIC DIAGRAM 2 25 CDP SCHEMATIC DIAGRAM 2 27 PRINTED CIRCUIT DIAGRAM 2 29 SECTION 3 CABINET MAIN CHASSIS MECHANISM EXPLODED VIEW 3 1 SECTION 4 REPLACEMENT PARTS LIST 4 1 CONTENTS ...

Page 2: ...itive lead Always remove the test instrument ground lead last 1 The service precautions are indicated or printed on the cabinet chassis or components When servicing follow the printed or indicated service precautions and service materials 2 The Components used in the unit have a specified conflammability and dielectric strength When replacing any components use components which have the same ratin...

Page 3: ...harges sufficient to damage ESD devices 5 Do not use freon propelled chemicals These can generate electrical charges sufficient to damage ESD devices 6 Do not remove a replacement ESD device from its protective package until immediately before you are ready to install it Most replacement ESD devices are packaged with leads electrically shorted together by conductive foam aluminum foil or comparabl...

Page 4: ...uency 10 7MHz 450kHz 450kHz Usable sensitivity 10dBµV 33dBµV 38dBµV Signal to noise ratio 60dB 50dB 50dB 3 COMPACT DISC SECTION Frequency response 40Hz 20kHz Channel separation 50dB 1kHz Signal to noise ratio 60dB 4 AUDIO SECTION Maximum output power 50W x 4 Frequency response 40Hz to 14 000Hz Speaker impedance 4Ω x 4 or 8Ω x 4 Signal to noise ratio 60dB NOTE The design and specifications are subj...

Page 5: ... supply circuitry Q401 Q404 CW001 pin25 IC201 pin44 NO Check laser circuitry CDP P43 TR1 IC101 IC201 IC301 Check focusing circuitry CDP PCB IC101 IC201 IC301 Check DISC NO Check tracking servo circuitry CDP PCB IC101 IC201 IC301 NO Check audio circuitry IC201 IC302 CDP PCB IC101 IC201 Is power turned on DISC loading Does initial reading occur Can disc be played Is audio output supplied OK ...

Page 6: ... Q505 Q506 YES Is u com IC201 Xin Xout terminal Pin 1 100 input OSC 4 5MHz NO CT201 CC201 CC202 defective YES Is u com IC201 keyin Pin7 Pin45 0volt input NO CN201 front PCB pattern defective YES Is u com IC201 Pin46 47 48 output waveform normal 5V NO IC201 pin46 48 front PCB pattern defective Is IC701 com1 com2 com3 output waveform normal Display LCD connector defective 5V NO IC701 Surrounding cir...

Page 7: ...s rotation normal Is there any irregularity in frequency YES Is RF signal normal without dropout NO Check voltage in the power supply circuitry Q505 R506 IC201 pin39 pin87 CDP PCB IC301 NO Leaf SW contact defective Connector defective Pattern short NO A B Does disc motor rotate Is RF wave output RF Is tracking servo operating Is the lower envelope of RF waveform flat Is signal output at TEO Is sig...

Page 8: ...C101 201 CDP PCB defective NO NO Reset SW defective Connector defective NO IC201 defective Has Pick up returned to the innermost position Does pick up stop after having moved to the innermost position IC201 Pin 25 Has laser power source returned to the TR1 CDP PCB TR1 collector voltage about 2 2V Flow laser current Both voltage of TR1 CDP PCB is about 1 0V NO YES R40 CDP PCB R40 CDP PCB Are data t...

Page 9: ...fective Is signal output at IC301 Pin1 2 CDP PCB NO IC301 defective YES YES YES Actuator short Connector short IC101 CDP PCB defective Connector short The waveform of RF HF is below figure Amplitude 0 5 1 0v NO YES IC101 CDP PCB defective TR1 IC101 CDP PCB surrounding circuitry defective Is FOK signal output RF HF 0 4V over OK FOK NO YES IC101 CDP PCB defective Is FOK signal to IC201 Pin41 C FOK N...

Page 10: ... at IC101 CDP PCB Pin31 ISTAT YES NO Pattern defective between IC201 Pin 72 73 75 76 CDP PCB and IC201 Main Is SMON signal output by IC201 CDP PCB Pin73 Is SMPO signal output by IC201 CDP PCB Pin75 YES NO IC101 305 CDP PCB defective Surrounding circuitry defective Has voltage at disc motor 0v YES Disc motor defective CN101 CDP PCB connector defective ISTAT FE1 ...

Page 11: ... 2 7 INTERNAL BLOCK DIAGRAM of ICs IC201 LC723764 Micro processor IC 1 PORT ASSIGNMENT ...

Page 12: ...CDP DISC Loading SW LOW DISC IN HIGH DISC OUT 23 S0 PC1 I CDP DISC LOAD SW LOW DISC OUT HIGH DISC IN 24 S1 PC0 I CDP DISC EJECT SW LOW DISC OUT HIGH DISC IN 25 XREST PB3 O CDP LSI RESET OUTPUT PORT 26 NC PB2 O 27 MLT PB1 O CDP LSI CONTROL DATA LATCH OUTPUT PORT 28 MDATA PB0 O CDP LSI CONTROL DATA OUTPUT PORT 29 OPTION IN PA3 I OPTION DIODE MATRIX INPUT PORT 30 OPTION IN PA2 I OPTION DIODE MATRIX I...

Page 13: ... NC PJ1 No connection 76 LO DX PJ0 O L OCAL DX MODE SELECTION PORT 77 LEVELMETER PI3 ADI7 I EQ INPUT PORT 78 RDS DATA PI2 ADI6 I RDS DATA INPUT PORT 79 E PLSDN PI1 ADI5 I I VOLUME LEFT ENCODER SWITCH Input PORT IOS1 8 XX1X 80 NC PI0 ADI4 No connection 81 T PULSEDN VSSADC I TUNER ENCODER Input Supplied Voltage Port 4 5V 5 5V 82 SD PH3 ADI3 I H RADIO SD CHECK 82 T PLSDN PH3 ADI3 I I SEARCH Right ENC...

Page 14: ... 2 10 IC301 LC75421M Electronic Volume controller IC PORT ASSIGNMENT ...

Page 15: ... 2 11 IC701 LD4104 LCD Driver IC Block Diagram Pin Diagram ...

Page 16: ...ervo control Tracking error amplifier Servo control Mirror Defect detector circuit Focus OK detractor circuit APC Auto Laser Power Control circuit for constant laser power FE bias focus servo offset adjustment free EF balance tracking error gain adjustment free Embedded audio post filter The circuit for Interruption countermeasure Double speed play available Operating voltage range 5V PIN CONFIGUR...

Page 17: ...H1 16 GC1I Amplifier negative input pin for gain and low pass filtering of DAC output CH1 17 RRC The pin for noise reduction of post filter bias 18 VSSP VSS for post filter 19 MUTEI The input pin for post filter muting control 20 ISET The input pin for current setting of focus search track jump and sled kick voltage 21 VREG The output pin of regulator 22 WDCK The clock input pin for auto sequence ...

Page 18: ...mparator input pin for tracking zero crossing detection 53 TE2 Tracking servo input pin 54 TE1 Tracking error amplifier output pin 55 LPFT The input pin of tracking error low pass filtering signal 56 DVDD The power supply pin for logic circuit 57 TDFCT The capacitor connection pin for tracking defect compensation 58 FE2 Focus servo input in 59 FE1 Focus error amplifier output pin 60 FDFCT The capa...

Page 19: ...mming amplifier inverting input pin 74 RFO RF summing amplifier output pin 75 IRF The input pin for AGC 76 EQO The output pin for AGC 77 RFI The input pin for EFM comparison 78 EQC The capacitor connection pin for AGC 79 EI Feedback input pin of E I V amplifier EF Balance control 80 GND GND for RF part Symbol Description ...

Page 20: ... 2 16 ...

Page 21: ...rminal2 of reference voltage L Floating 17 VREFL1 I Input terminal1 of reference voltage L GND connection 18 AVDD2 Analog VCC2 19 RCHOUT O Right Channel audio output through D A converter 20 LCHOUT O Left Channel audio output through D A converter 21 AVSS2 Analog ground2 22 VREFH1 I Input terminal1 of reference voltage H VDD connection 23 VREFH2 I Input terminal2 of reference voltage H Floating 24...

Page 22: ...ection RA4 51 C2FL I O C2 decoder flag RA5 H When the processing C2 code is impossible correction status 52 PBCK I O Output of VCO 2 4 3218MHz RA6 53 DVSS2 I O Digital ground 2 54 FSDW I O Window or unprotected frame sync RA7 55 ULKFS I O Frame sync protection state RA8 56 JIT I O Display of either RAM overflow or underflow for 4 frame jitter margin RA9 57 C4M I O Only monitoring signal 4 2336MHz ...

Page 23: ...pindle servo error signal 73 SMON O ON OFF control signal for spindle servo 74 DVDD2 Digital VDD2 75 SMDP O Spindle Motor drive Rough control in the SPEED mode Phase control in the PHASE mode 76 SMSD O Spindle Motor drive Velocity control in the PHASE mode 77 BCKI I Audio data bit clock input of 48 bit Slot 2 1168MHz 78 TESTV I TEST input terminal GND connection 79 DSPEED I TEST input terminal VDD...

Page 24: ... 2 20 ...

Page 25: ... PGND1 PGND2 PGND3 PGND4 MGG153 OUT4 OUT4 OUT3 DIAGNOSTIC OUT2 V OUT1 OUT3 OUT2 OUT1 21 20 22 19 17 9 5 7 4 2 23 16 10 11 12 13 14 30 K 30 K 30 K 30 K IN1 MODE IN2 SGND IN3 IN4 8 1 15 18 6 3 ref VP1 VP2 VP3 VP4 Vref VDIAG ...

Page 26: ... 2 22 MEMO ...

Page 27: ...2 23 2 24 BLOCK DIAGRAM ...

Page 28: ... MAIN SCHEMATIC DIAGRAM 2 25 2 26 ...

Page 29: ...2 27 2 28 CDP SCHEMATIC DIAGRAM ...

Page 30: ...2 29 2 30 PRINTED CIRCUIT DIAGRAM 1 FRONT PCB BOTTOM 1 FRONT PCB TOP 2 TRIM PCB BOTTOM 2 TRIM PCB TOP ...

Page 31: ...2 31 3 32 3 MAIN PCB BOTTOM ...

Page 32: ...3 MAIN PCB TOP 2 33 3 34 ...

Page 33: ...2 35 2 36 4 CDP BOTTOM ...

Page 34: ...4 CDP TOP 2 37 2 38 ...

Page 35: ...6 333 456 A43 327 330 328 334 329 323 321 320 265 A41 264 253 255 254 322 331 325 324 253 250 A42 288 CAUTION Exposed blade will cause severe injury SECTION 3 CABINET MAIN CHASSIS MECHANISM NOTE Refer to SECTION 4 REPLACEMENT PARTS LIST in order to look for the part number of each part ...

Page 36: ...MEMO MEMO ...