LG TCH-M900, Service Manual

Page 1: ...TROUBLESHOOTING GUIDE 2 3 WAVEFORMS OF MAJOR CHECK POINT 2 11 INTERNAL BLOCK DIAGRAM of ICs 2 13 BLOCK DIAGRAM 2 25 SCHEMATIC DIAGRAM 2 27 MAIN SCHEMATIC DIAGRAM 2 27 FRONT SCHEMATIC DIAGRAM 2 29 CDP SCHEMATIC DIAGRAM 2 31 PRINTED CIRCUIT DIAGRAM 2 33 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: ...Hz 520 1 620kHz Intermediate frequency 10 8MHz 450kHz Usable sensitivity 12dBµV 32dBµV Signal to noise ratio 55dB 45dB 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 Speaker impedance 4Ω x 4 or 8Ω x 4 NOTE The design and specifications are subject to change without notice in the sourse of pro...

Page 5: ...dio output supplied Check power supply circuitry Q260 Q380 Q381 IC401 Pin76 IC201 Pin2 Check loading supply circuitry Q350 Q351 PN505 IC401 Pin27 Check laser circuitry Q501 IC502 Check focusing circuitry Q501 IC502 Check DISC Check tracking servo circuitry Q501 IC502 Check audio circuitry IC502 IC601 IC801 OK YES YES YES YES YES YES NO NO NO NO NO 1 No Power ...

Page 6: ... X401 C413 C414 defective Q260 PN401 front PCB pattern defective IC401 Pin38 40 47 48 front PCB pattern defective IC901 Surrounding circuit PCB pattern defective Is u com IC401 reset circuit normal Pin10 Is u com IC401 keyin Pin16 44 71 5volt input Is u com IC401 Pin 38 40 47 48 output waveform normal Is IC901 Com1 Com2 Com3 output waveform normal Display LCD connector defective Is u com IC401X1 X...

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Page 15: ...M CN503 1 9 2 1 1 8 20 during normal play 2 SLED DRIVE AND MOTOR WAVEFORM IC504 pin5 1 4 when focus search 3 FOCUS DRIVE AND MOTOR WAVEFORM R5 1 3 IC504 pin 1 5 When focus search failed or there is no disc on the tray There is disc on tray and focus search success ...

Page 16: ...SPINDLE DRIVE AND MOTOR WAVEFORM IC504 pin6 1 2 when TOC reading 5 TRACK DRIVE AND MOTOR WAVEFORM R508 IC504 pin23 during normal play 6 RF TRACKING AND FOCUS ERROR WAVEFORM IC502 pin8 2 1 23 during normal play ...

Page 17: ... 2 13 IC401 LC875465B 1 PORT ASSIGNMENT INTERNAL BLOCK DIAGRAM of ICs ...

Page 18: ... 2 14 2 PORT DESCRIPTION ...

Page 19: ...t to be used Not to be used Not to be used Not to be used To CD changer data output For diode option check signal 1 output Refer to Option Diode For diode option check signal 2 output Refer to Option Diode For diode option check signal 1 or 2 input2 Refer to Option Diode For diode option check signal 1 or 2 input1 Refer to Option Diode For diode option check signal 1 or 2 input0 Refer to Option Di...

Page 20: ...Low Clock for interfacewith volumecontroller SystemPower supplier ON output On High Off Low Description To volumecontroller data output To power amp MUTE command output Mute High Sound Low Namein Micom PPWR_MUTE PC6 A6 PEV_CLK PC5 A5 PPWR Namein Model PEV_DO FromISO jack ACC signal input ACC On Low ACC Off High Not to beused CD changer power supplier ON output CDC On High CDC Off Low PACC N C PCDC...

Page 21: ... 2 17 2 Block Diagram ...

Page 22: ...l output absolute value 30 SPPOL O Spindle drive signal output polarity 31 TRVP O Traverse drive signal output positive polarity 32 TRVM O Traverse drive signal output negative polarity 33 TRVP2 O Traverse drive signal output 2 positive polarity 34 TRVM2 O Traverse drive signal output 2 negative polarity 35 TRP O Tracking drive signal output positive polarity 36 TRM O Tracking drive signal output ...

Page 23: ...ignal output 78 PMCK O 88 2 kHz clock signal output 79 TX O Digital audio interface signal output 80 FLAG O Flag signal output 81 NRST I LSI reset signal input 82 NTEST I Test mode setting input 83 DVSS3 I Ground 3 for digital circuits 84 X1 I Crystal oscillator circuit input 85 X2 O Crystal oscillator circuit output 86 IOVDD2 I Power supply 2 for digital I O 87 DVDD2 I Power supply 2 for internal...

Page 24: ...KE CS RAS CAS WE L U DQM LDQM LWCBR LCAS Bank Select LWE LDQM DQI Data Input Regidter 512K x 16 512K x 16 Column Decoder Latency Burst Length Programming Register Timing Register Address Register Row Decoder LCBR LRAS Sense AMP I O Control Output Buffer Col Buffer Row Buffer Refresh Counter ...

Page 25: ...he positive going edge of the CLK with CAS low Enables column access WE Write Enable Enables write operation and row precharge Latches data in starting from CAS WE active L U DQM Data Input Output Mask Makes data output Hi Z tSHZ after the clock and masks the output Blocks data input when L U DQM active DQ0 15 Data Input Output Data inputs outputs are multiplexed on the same pins VDD VSS Power Sup...

Page 26: ... 2 22 IC505 AMC1117 BLOCK DIAGRAM ...

Page 27: ... Control LIN2 LIN2 LIN1 LOUT LIN LOUD_L BOUT_L BIN_L TREB_L LFOUT Mute Mute Mute Mute Speaker ATT Speaker ATT Speaker ATT Speaker ATT LROUT CLK DATA DGND RFOUT RROUT LIN1 2 11 10 9 13 14 15 17 16 12 19 18 4 25 23 28 27 26 24 22 3 1 7 6 8 21 20 5 Supply Bass Serial Bus Decoder Latches Bass Treble Treble Voume Loudness Voume Loudness ...

Page 28: ...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 IC901 LC75811 ...

Page 29: ...7933 RF IC AN22004A OP AMP S4560 RADIO VCC Q310 ZD313 LINE SW E VOLUME 9 4V REG Q360 ZD361 AUDIO MUTE CONTROL Q801 POWER 5V Q282 Q283 7 5V REG Q320 351 3 3V REG IC805 U COM uPD789166 KEY MATRIX RESISTOR RADER RESET IC203 5V CONVERT Q260 D261D262 REG 10V IC402 LCD DRIVER LC75811W LCD DISPLAY REG 10V IC403 PHONE MUTE Q280 281 ACC DETECTOR Q230 D231 D232 REMOTE CONTROL Q320 321 ANT CONTROL Q390 391 P...

Page 30: ... SCHEMATIC DIAGRAM MAIN SCHEMATIC DIAGRAM 2 27 2 28 ...

Page 31: ...2 29 2 30 FRONT SCHEMATIC DIAGRAM ...

Page 32: ...2 31 2 32 SCHEMATIC DIAGRAM CDP SCHEMATIC DIAGRAM ...

Page 33: ...2 33 2 34 PRINTED CIRCUIT DIAGRAM 1 LED P C BOARD COMPONENT SIDE 2 FRONT P C BOARD COMPONENT SIDE 2 FRONT P C BOARD SOLDER SIDE ...

Page 34: ...2 35 2 36 3 MAIN P C BOARD ...

Page 35: ...2 37 2 38 4 CDP P C BOARD ...

Page 36: ...267 266 260 261 262 263 259 257 256 253 252 250 251 254 255 264 258 A46 278 276 272 271 275 277 454 A45 270 273 452 282 452 281 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 ...