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LG LH-T750TB Service Manual
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LG LH-T750TB Service Manual

Dvd/cd receiver
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DVD/CD RECEIVER
SERVICE MANUAL
MODELS : LH-T750TB/LH-T751TB
LHS-75TBC,
LHS-75TBS, LHS-75TBW

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Summary of Contents for LG LH-T750TB

  • Page 1 DVD/CD RECEIVER SERVICE MANUAL MODELS : LH-T750TB/LH-T751TB LHS-75TBC, LHS-75TBS, LHS-75TBW...

  • Page 2: Table Of Contents

    [CONTENTS] SECTION 1. GENERAL • SERVICING PRECAUTIONS ..........1-2 •...

  • Page 3: Section 1. General

    SECTION 1. GENERAL SERVICING PRECAUTIONS NOTES REGARDING HANDLING OF THE PICK-UP 1. Notes for transport and storage 1) The pick-up should always be left in its conductive bag until immediately prior to use. 2) The pick-up should never be subjected to external pressure or impact. Storage in conductive bag Drop impact 2.
  • Page 4 NOTES REGARDING COMPACT DISC PLAYER REPAIRS 1. Preparations 1) Compact disc players incorporate a great many ICs as well as the pick-up (laser diode). These components are sensitive to, and easily affected by, static electricity. If such static electricity is high voltage, components can be damaged, and for that reason components should be handled with care.

  • Page 5: Esd Precautions

    ESD PRECAUTIONS Electrostatically Sensitive Devices (ESD) Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD devices are integrated circuits and some field-effect transistors and semiconductor chip components. The following techniques should be used to help reduce the incidence of component damage caused by static electricity.

  • Page 6: Specifications

    SPECIFICATIONS GENERAL Power supply Refer to main label Power consumption Refer to main label Weight 3.9 kg External dimensions (W x H x D) 430 x 54 x 350 mm Operating conditions Temperature: 5°C to 35°C, Operation status: Horizontal Operating humidity 5% to 85% CD/DVD Laser...

  • Page 7: Section 2. Audio Part

    SECTION 2. AUDIO PART AUDIO TROUBLESHOOTING GUIDE 1. POWER SUPPLY CIRCUIT...
  • Page 8 2. FRONT CIRCUIT (1/2) CN902 CN902 : -32.4 VKK PIN3 : -27.5 FL- PIN4 : -23.7 FL+ PIN9 : +5.0...
  • Page 9 3. FRONT CIRCUIT (2/2)

  • Page 10: Wiring Diagram

    WIRING DIAGRAM WIRELESS SPEAKER TERMINAL OPTICAL SCART OPTION AV1,2 JACK TUNER COMPONENT MONITOR OUT S-VIDEO OUT PN302 PN105 MAIN PCB 30PIN AMP PCB PDM01 PDM03 PN103 PN104 PN801 23PIN 11PIN 24PIN 23PIN CN350 PN902 PN303 14PIN 14PIN 6PIN 5PIN SMPS PCB FRONT FRONT PN001...

  • Page 11: Block Diagram

    BLOCK DIAGRAM SPDIF 12.288MHz Optical Tuner-L/R (A)(T_CE,T_DO,T_DI,T_CLK,T_RDS_DATA,T_RDS,CLK) Tuner AD-DATA LRCK CS 5340 PS 9818 AV1-L/R AD-BCK CS 8406 Audio s/w Fs = 48kHz (PWM) AV2-L/R AD-LRCK ADAT 0,1,2,3 Bu 4052 (slave) (FL/R,RL/R, C/SW) /RST-AD 8406_SDI,8406_SDO CTL-A/B 8406_CLK,8406_CE AV1-CVBS 8406_RST,8406_INT (A) HP_DET Video S/W (option) AV2-CVBS...

  • Page 12: Schematic Diagrams

    SCHEMATIC DIAGRAMS 1. POWER SCHEMATIC DIAGRAM_1 NOTES) Warning NOTES) Parts that are shaded are critical NOTES) With respect to risk of fire or NOTES) electricial shock.
  • Page 13 2. POWER SCHEMATIC DIAGRAM_2 2-10 2-11...
  • Page 14 3. MICOM SCHEMATIC DIAGRAM 2-12 2-13...
  • Page 15 4. FRONT SCHEMATIC DIAGRAM 2-14 2-15...
  • Page 16 5. DSP&AMP SCHEMATIC DIAGRAM 2-16 2-17...
  • Page 17 6. I/O SCHEMATIC DIAGRAM 2-18 2-19...
  • Page 18 7. MAIN MIC SCHEMATIC DIAGRAM 2-20 2-21...
  • Page 19 PRINTED CIRCUIT BOARD DIAGRAMS 1. MAIN/DVD P.C. BOARD DIAGRAM ( TOP VIEW ) 2-22 2-23...
  • Page 20 2. MAIN/DVD P.C. BOARD DIAGRAM ( BOTTOM VIEW ) 6870R7505AC 2-24 2-25...
  • Page 21 3. FRONT MIC P.C. BOARD 6870R7507AA 2-26 2-27...
  • Page 22 4. SMPS P.C. BOARD 5. MIC P.C. BOARD ( 5 TOOL ) ( TOP VIEW ) LOCATION GUIDE NOTES) Warning NOTES) Parts that are shaded are critical NOTES) With respect to risk of fire or NOTES) electricial shock. ( 7 TOOL ) ( BOTTOM VIEW ) LOCATION GUIDE NOTES)
  • Page 23 6. AMP P.C. BOARD ( TOP VIEW ) ( BOTTOM VIEW ) 2-30 2-31...

  • Page 24: Section 3. Dvd & Amp Part

    SECTION 3. DVD & AMP PART ELECTRICAL TROUBLESHOOTING GUIDE 1. System operation flow Power On 1. 8082 initializes SERVO, DSP & RISC registers 2. Write RISC code to SDRAM 3. Reset RISC Show LOGO Tray Closed? Tray Close to Closed position SLED at Inner Side? SLED Moves to Inner Position...
  • Page 25 2. Test & debug flow TEST Check the AC Vol tage Check the POWER PART Power PCBA (110V or 220V) Switch on the Power PCBA Is the DC Voltage outputs OK? Check the POWER PART (-44V, -22V, -26.5V, ±12V, 5.6V, 3.3V, 5V, 7V, 8V) Are 3.3V and 5V DC Check the regulators or diode.
  • Page 26 , 115.
  • Page 28 ES6698. ES6698. ES6698.
  • Page 30 PWM IC Check connection between received correct data IC300 ABCK, ALRCK, stream? ASDAT Normal Check the related circuit of PWM IC out?(IC301) PWM.(Check Audio out Pins52, 54, 55, 59,62, 68 Check Digital Amp circuit (IC701, IC702, IC703, IC704)
  • Page 31 3. AUDIO µ-COM Circuit(DVD & AMP) POWER ON Does CD/DVD appear Does AV1, TV Audio, AV1 opt. at FLD? and FM 87.5 appear at FLD Does Loading appear Does it appear DVD Error at FLD? at FLD? Does no Disc or Time Check power part of Main Refer to SMPS.
  • Page 32 DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING 1. SYSTEM 27MHz CLOCK,RESET,FLASH R/W SIGNAL 1) ES6698FD main clock is at 27MHz(X501) 3.8V, 27MHz FIG 1-1 2) ES6698FD reset is high active. Power Cord in 5.2VA PWR_CTL(SYSTEM µ-COM) IC501 PIN83) M_RESET(IC501 PIN 207) URST(IC501 PIN 188) FIG 1-2...
  • Page 33 3) Flash R/W enable signal during download(Downloading) FRD(IC500 PIN 28) FWR(IC500 PIN 11) FIG 1-4 2. SDRAM CLOCK 1) ES6698FD main clock is at 27MHz(X501) DCLK = 93MHz, Vp-p=2.2, Vmax=2.7V (IC503 PIN 38) FIG 2-1 3-10...
  • Page 34 3. TRAY OPEN/CLOSE SIGNAL 1) Tray open/close waveform OPEN((PDM03 PIN7) CLOSE(PDM03 PIN8) TROPEN(IC402 PIN 4) TRCLOSE(IC402 PIN 5) FIG 3-1 2) Tray close waveform OPEN((PDM03 PIN7) CLOSE(PDM03 PIN8) TROPEN(IC402 PIN 4) TRCLOSE(IC402 PIN 5) FIG 3-2 3-11...
  • Page 35 3) Tray open waveform OPEN(PDM03 PIN7) CLOSE(PDM03 PIN8) TROPEN(IC402 PIN 4) TRCLOSE(IC402 PIN 5) FIG 3-3 4. SLED CONTROL RELATED SIGNAL (NO DISC CONDITION) FMSO(2.0V/1.4V/1.0V) (IC501 PIN 19) STBY(5V) – (IC401 PIN 50) SL+(4.7V/3.6V/1.9V) (IC404 PIN 12) SL-(5.3V/3.7V/2.5V) (IC404 PIN 11) FIG 4-1 3-12...
  • Page 36 5. LENS CONTROL RELATED SIGNAL(NO DISC CONDITION) FOSO(1.5V/1.4V/1.3V) (IC501 PIN 12) F+(4.0V/3.6V/3.2V) (IC404 PIN 14) F-(4.0V/3.6V/3.2V) (IC404 PIN 13) FIG 5-1 6. LASER POWER CONTROL RELATED SIGNAL(NO DISC CONDITION) MDI1(0V/180mV) (IC401 PIN 26) LD01(5.0V//3.5V) IC401 PIN 20) LD02(5.0V/3.6V) (IC401 PIN 21) FIG 6-1 3-13...
  • Page 37 7. DISC TYPE JUDGEMENT WAVEFORMS F+(IC404 PIN 14) FE(IC401 PIN 40) RFL(IC401 PIN 19) FIG 7-1 (DVD) F+(IC404 PIN 14) FE(IC401 PIN 40) RFL(IC401 PIN 19) FIG 7-2 (DVD) 3-14...
  • Page 38 F+(IC404 PIN 14) FE(IC401 PIN 40) RFL(IC401 PIN 19) FIG 7-3 (CD) F+(IC404 PIN 14) FE(IC401 PIN 40) RFL(IC401 PIN 19) FIG 7-4 (CD) 3-15...
  • Page 39 8. FOCUS ON WAVEFORMS FE(IC401 PIN 40) FOSO(IC501 PIN12) F+(IC404 PIN 14) F-(IC404 PIN 13) FIG 8-1 (DVD) FE(IC401 PIN 40) FOSO(IC501 PIN12) F+(IC404 PIN 14) F-(IC404 PIN 13) FIG 8-2 (CD) 3-16...
  • Page 40 9. SPINDLE CONTROL WAVEFORMS (NO DISC CONDITION) DMSO(1.4V/1.8V) (IC501 PIN 18) SP-(3.6V/2.4V) (IC404 PIN 18) SP+(3.6V/4.8V) (IC404 PIN 17) FIG 9-1 10. TRACKING CONTROL RELATED SIGNAL(System checking) TE(IC401 PIN 39) TRSO(IC501 PIN 13) T-(IC404 PIN 16) T+(IC404 PIN 15) FIG 10-1(DVD) 3-17...
  • Page 41 TE(IC401 PIN 39) TRSO(IC501 PIN 13) T-(IC404 PIN 16) T+(IC404 PIN 15) FIG 10-2(CD) 11. RF WAVEFORM RFOP(2.3V/1.1V) (IC401 PIN 55) RFON(0.8V/2.0V) (IC401 PIN 57) FIG 11-1 3-18...
  • Page 42 12. ES6698FD VIDEO OUTPUT WAVEFORMS 1) Full colorbar signal(COMPOSIT) (IC501 PIN 110) FIG 12-1 2) Y (IC501 PIN 113) FIG 12-2 3-19...
  • Page 43 13. AUDIO OUTPUT FROM PWM IC 1) Audio L/R (IC301 PIN 68, 49) FIG 13-1 2) Audio related Signal ASDATA3 ASDAT0(IC501 PIN 117) ABCK(IC501 PIN 123) ALRCK(IC501 PIN 116) FIG 13-2 3-20...
  • Page 44 14. DVD & AMP WAVEFORMS • R310 → TP301 • R320 → TP311 R311 TP302 R321 TP312 • R312 → TP303 • R318 → TP307 R313 TP304 R319 TP308 • R314 → TP305 • R318 → TP309 R315 TP304 R319 TP310 3-21...

  • Page 46: Dvd Part Schematic Diagrams

    DVD PART SCHEMATIC DIAGRAMS 1. DVD MPEG & DSP SCHEMATIC DIAGRAM 3-22 3-23...
  • Page 47 2. RF & SERVO SCHEMATIC DIAGRAM 3-24 3-25...
  • Page 48 3. FRONT MIC SCHEMATIC DIAGRAM(KARAOKE MODEL ONLY) 3-26 3-27...
  • Page 49 4. USB CONTROLLER SCHEMATIC DIAGRAM 3-28 3-29...
  • Page 50 5. AMP SCHEMATIC DIAGRAM ( 5TOOL ) 3-30 3-31...
  • Page 51 6. AMP SCHEMATIC DIAGRAM ( 7TOOL ) 3-32 3-33...

  • Page 52: Section 4. Exploded Views

    SECTION 4. EXPLODED VIEWS • CABINET AND MAIN FRAME SECTION OPTIONAL PART NOTES) THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. JACK OPTION...
  • Page 53 • DECK MECHANISM EXPLODED VIEW NSP : Non SVC Parts LOCA. NO. PART NO. DESCRIPTION SPECIFICATION REMARKS 6721RJ0870E DECK ASSEMBLY,AUDIO HOME THEATER LH-TK750/550/250 4861R-0016B CLAMP ASSEMBLY DISC DP7 - SH 015B 3041R-T001A BASE ASSEMBLY MAIN DP-9T-ESS 3041R-T001B BASE ASSEMBLY SLED DP-9T-DI -ESS-SAMSUNG 015A 3300R-0547A PLATE...
  • Page 54 • Packing Accessory Section OPTIONAL PART 811 PLUG ASS'Y 1WAY(YELLOW) MICRO PHONE FILTER(CIRC) 824 ANTENNA LOOP(AM) 825 ANTENNA (FM) BATTERY INSTRUCTION ASSEMBLY REMOCON AC ADAPTOR PACKING, CASING PACKING, CASING...
  • Page 56 SECTION 5. SPEAKER SECTION • CENTER SPEAKER MODEL : LHS-75TBC OPTIONAL PARTS LHS-75TBC XHS-75TBS ONLY...
  • Page 57 • FRONT/REAR SPEAKER MODEL : LHS-75TBS OPTIONAL PARTS LHS-75TBS XHS-75TBS ONLY...
  • Page 58 • SUB WOOFER SPEAKER MODEL : LHS-75TBW...

This manual is also suitable for:

Lh-t751tbLhs-75tbcLhs-75tbsLhs-75tbw

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