LG MCV903 Service Manual
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LG MCV903 Service Manual

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Internal Use Only
Website http://biz.lgservice.com
MINI Hi-Fi SYSTEM
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT, READ THE "SAFETY PRECAUTIONS" IN THIS MANUAL.
MODEL : MCV903
(MCS903F,MCS903S,MCS903W,MCS903AW)

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  • Page 1 Internal Use Only Website http://biz.lgservice.com MINI Hi-Fi SYSTEM SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS” IN THIS MANUAL. MODEL : MCV903 (MCS903F,MCS903S,MCS903W,MCS903AW)
  • Page 2 REPLACEMENT PARTS LIST ..........5-1 Copyright © 2008 LG Electronics. Inc. All right reserved.

  • Page 3: Section 1. General

    Take care not to use too much of this alcohol on the swab, and do not allow the alcohol to get inside the pick-up. LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 4: Notes Regarding Compact Disc Player Repairs

    NOTE: 1. To operate the RESET jump wire, pull the volume rotary knob and release it. 2. If you wish to operate the RESET jump wire, it is necessary to unplug the power cord. Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only...

  • Page 5: Esd Precautions

    THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 6: Location Of Users Controls

    • Look for radio stations automatically • PORTABLE IN • PHONES • Starts or pauses recording • PORTABLE • MIC 1/MIC 2 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 7: Remote Control

    Search for a section within a track the display changes in the following order, Play Fast backward or Forward LINK ON¡SURROUND 1¡SURROUND 2. LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 8: Specifications

    315 x 432 x 356 mm Net Weight (1EA) 4.4 kg 8.3 kg 9.8 kg Designs and specifications are subject to change without pior notice. Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 9 1. INSERT USB DEVICE AT USB FUNCTION READ FIRMWARE WRITE 00 .. 100 UPDATED POWER OFF AUTOMATICALLY 2. WHEN COMPLETED, REMOVE USB DEVICE. LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 10 NO USB 1. INSERT USB DEVICE AT USB FUNCTION READ FIRMWARE FINISH UPDATED POWER OFF MANUALLY 2. WHEN COMPLETED, REMOVE USB DEVICE. Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 11 LGE Internal Use Only 1-10 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 12: Section 2. Exploded Views

    EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. CABLE4 FRONT CABLE3 CABLE1 CABLE2 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 13: Tape Deck Mechanism Exploded View

    FOR WOW FLUTTER WHEN NECESSARY RING FW MAYBE ADDED FOR WOW FLUTTER WHEN NECESSARY RING FW MAYBE ADDED FOR WOW FLUTTER WHEN NECESSARY LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 14 2. TAPE DECK MECHANISM (A/R & A/S : LEFT A/S DECK) RING FW MAYBE ADDED FOR WOW FLUTTER WHEN NECESSARY Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 15: Cd Mechanism Exploded View

    CD MECHANISM EXPLODED VIEW LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 16: Speaker Exploded View

    SPEAKER EXPLODED VIEW • FRONT SPEAKER (MCS903F) A80L A80BL A80R A80BR A80A WIRE80 WIRE81 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 17 • REAR SPEAKER (MCS903S) A60R A60R A60BL A60BR WIRE60 WIRE61 A60A LGE Internal Use Only 2-10 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 18 • PASSIVE SUBWOOFER (MCS903W) A90B A90A Copyright © 2008 LG Electronics. Inc. All right reserved. 2-11 LGE Internal Use Only Only for training and service purposes...
  • Page 19 • PASSIVE SUBWOOFER (MCS903AW) A70B A70A WIRE70 LGE Internal Use Only 2-12 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 20: Packing Accessory View

    825 ANTENNA Plug Ass'y, 2Way(Yellow) 808 Battery 826 Microphone Remote Control 832 DISC Instruction Ass'y 830 AC Adaptor Packing Packing Copyright © 2008 LG Electronics. Inc. All right reserved. 2-13 LGE Internal Use Only Only for training and service purposes...
  • Page 21 LGE Internal Use Only 2-14 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 22: Section 3. Audio Electrical Part

    IC101 KIA7042 part input 5V? KIA7042 Check the IC100 Is IC101 KIA7042 87F5NC8A 4 output 4.3V? PIN power Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 23 Check the operation status of Check IC100 87F5NC8A KIA7031 output R191 10K and R110 4.7K 8 PIN power. power Replace the related parts. LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 24 Check the IC100 14.40.56.89 Refer to MICOM Par I,II Troubleshooting input power (4.8V or higher) Check the operation status of X101:32.768KHz and X100:9.8304MHz Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 25: Fld Display Check

    28 PIN ¡ PIN CLK Check the data at both terminals of LINE R330,331,332 Replace the related part. Check the related part FLT turned on LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 26 Refer to micom 81 PIN DATA 82 PIN CLK Check MICOM power 5V troubleshooting. Check the related part. Replace the related parts. Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 27 (MC4580) 2,6PIN Replace the related part Check the output waveform of the PN709 6 PIN L_ CH 8 PIN R_ CH LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 28 Replace the related part Check the IC801( MC4580) Check the input waveform of IC801. 4PIN VSS, 8PIN VDD power Replace the related part Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 29 16PINVDD, 8PIN VSS power Replace the related part Check the output waveform of the PN709 6 PIN L_ CH 8 PIN R_ CH LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 30: Tape Play Part Check

    Check the IC201 Check the IC202 10 PIN 14 PIN MUTE HIGH operation operation Replace the related part Check the related part Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 31: Tape Rec Part Check

    HIGH operation BASE HIGH oscillation Replace the related part . Check P2203 5.3 PIN input . Check 8 PIN ERASE input LGE Internal Use Only 3-10 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 32 Check the P7302 15PIN input (MAIN PCB Ass`y) Check the input at both terminals of R804,812 Check the IC603 1, 2PIN input Copyright © 2008 LG Electronics. Inc. All right reserved. 3-11 LGE Internal Use Only Only for training and service purposes...
  • Page 33 Refer to SMPS 9PIN 5V Troubleshooting. Check IC505 Check Check CN701 input 5V and IC505 input power 9PIN 5V output 3.3V LGE Internal Use Only 3-12 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 34 Check Replace the the output waveform REST check at both terminals of related part R665 Replace the related part Copyright © 2008 LG Electronics. Inc. All right reserved. 3-13 LGE Internal Use Only Only for training and service purposes...

  • Page 35: Pwm Modulation Part Check

    23 PIN SS0IND i n put part 20 PIN_LRCK 23 PIN_SS0IND(R655¡100 Ω) 23 PIN_SS0IND i n put Check the waveform waveform check at botht il LGE Internal Use Only 3-14 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 36 Replace the related power at both R554,553,552 part terminals of output Check DA-A_MUET (R539) LOW and SW-MUTE (R540) LOW operation Copyright © 2008 LG Electronics. Inc. All right reserved. 3-15 LGE Internal Use Only Only for training and service purposes...
  • Page 37 R859,860 Check R857,861 P7302 18PIN,16PIN Check Q803 BASE Check HP output (check LOWE the abnormal operation of SIG 0.9V) LGE Internal Use Only 3-16 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 38: Power Amp Part Check

    Check the power at both Replace the related part terminals of L754 +9V, terminals of the said part L753 -9V Copyright © 2008 LG Electronics. Inc. All right reserved. 3-17 LGE Internal Use Only Only for training and service purposes...
  • Page 39 IC701 1,6PIN R-CH, 17,22PIN L-CH output waveform Check the Replace the related part output LINE COIL LGE Internal Use Only 3-18 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 40: Internal Block Diagram Of Ics

    INTERNAL BLOCK DIAGRAM OF ICs 1. AK5358 • BIOCK DIAGRAM 2. BU4052 • BIOCK DIAGRAM Copyright © 2008 LG Electronics. Inc. All right reserved. 3-19 LGE Internal Use Only Only for training and service purposes...

  • Page 41: Pin Configuration

    3. LC87F5NC8A_AUDIO MICOM • PIN CONFIGURATION LGE Internal Use Only 3-20 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 42 4. PS9830B_PWM IC • BIOCK DIAGRAM 5. EM636165_SDRAM • BIOCK DIAGRAM Copyright © 2008 LG Electronics. Inc. All right reserved. 3-21 LGE Internal Use Only Only for training and service purposes...
  • Page 43 6. MLC3895_DSP • PIN CONFIGURATION 7. IP9010_MOTOR IC • BIOCK DIAGRAM LGE Internal Use Only 3-22 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 44 8. BU9543KV_MOTOR IC • PIN CONFIGURATION 9. S-24CS16A01_EEPROM IC • BIOCK DIAGRAM Copyright © 2008 LG Electronics. Inc. All right reserved. 3-23 LGE Internal Use Only Only for training and service purposes...

  • Page 45: System Block Diagram

    • S-24CS16A01_EEPROM IC • SYSTEM BLOCK DIAGRAM LGE Internal Use Only 3-24 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 46: Functional Block Diagram

    11. S29AL008D_FLASHIC • FUNCTIONAL BLOCK DIAGRAM Copyright © 2008 LG Electronics. Inc. All right reserved. 3-25 LGE Internal Use Only Only for training and service purposes...
  • Page 47 12. A12237_DECK IC • BIOCK DIAGRAM 13. DF350W01FH_WOOFER AMP IC • BIOCK DIAGRAM LGE Internal Use Only 3-26 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 48 14. DF330W20FH_AMP IC • BIOCK DIAGRAM Copyright © 2008 LG Electronics. Inc. All right reserved. 3-27 LGE Internal Use Only Only for training and service purposes...
  • Page 49 LGE Internal Use Only 3-28 Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 50: Wiring Diagram

    Bíd to Bíd DOUBLE DECK Bíd to Bíd MECHANISM MAIN AMP FRONT PCB SUB AMP Portable LED_L LED_R CD_KEY 3-29 3-30 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 51: Main & Front Block Diagram

    USB HOST 74HC4094 MUTE BA3308 MIC SIG. AK5358 TUR+/-, OP/CL AK5358 EXPANDER OPAMP (ALC) DMA[0:11] MD SWITCH, RESET DB[0:15] D+/D- 3-31 3-32 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 52 USB CON MCS LOGIC MCS LOGIC SDRAM SDRAM IPOD_DET IPOD_TX IPOD_READY FLASH FLASH POWER 3.3V IPOD CON1 IPOD CON2 3-33 3-34 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 53: Smps Schematic Diagram

    2008.01.25 NOTE) Parts that are shaded are critical NOTE) With respect to risk of fire or NOTE) electricial shock. 3-35 3-36 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 54 NOTE) Parts that are shaded are critical 2008.01.25 NOTE) With respect to risk of fire or NOTE) electricial shock. 3-37 3-38 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 55 3. MICOM SCHEMATIC DIAGRAM 2008 01 25 3-39 3-40 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 56: Interface Schematic Diagram

    4. INTERFACE SCHEMATIC DIAGRAM 2008.01.25 3-41 3-42 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 57: Deck Schematic Diagram

    5. DECK SCHEMATIC DIAGRAM 2008.01.25 3-43 3-44 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 58 6. MAIN AMP SCHEMATIC DIAGRAM 2008.01.25 3-45 3-46 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 59: Woofer Amp Schematic Diagram

    7. WOOFER AMP SCHEMATIC DIAGRAM 2008.01.25 3-47 3-48 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 60: Front Schematic Diagram

    8. FRONT SCHEMATIC DIAGRAM 2008.01.25 3-49 3-50 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 61 9. LED_L SCHEMATIC DIAGRAM 2008.01.25 3-51 3-52 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 62 10. LED_R SCHEMATIC DIAGRAM 2008.01.25 3-53 3-54 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 63 11. CD-KEY SCHEMATIC DIAGRAM 2008.01.25 3-55 3-56 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 64 12. MIC/HP/PT SCHEMATIC DIAGRAM 2008.01.25 3-57 3-58 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 65: Printed Circuit Board Diagrams

    1. SMPS P.C. BOARD DIAGRAM NOTE: Warning Parts that are shaded are critical With respect to risk of fire or electrical shock. 3-59 3-60 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 66 2. MAIN P.C. BOARD DIAGRAM ( TOP VIEW ) 3-61 3-62 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 67 2-1. MAIN P.C. BOARD DIAGRAM ( BOTTOM VIEW ) 3-63 3-64 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 68 3-1. MAIN AMP P.C. BOARD DIAGRAM ( TOP VIEW ) 3-65 3-66 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 69 3-2. MAIN AMP P.C. BOARD DIAGRAM ( BOTTOM VIEW ) 3-67 3-68 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 70: Front P.c. Board Diagram

    4. FRONT P.C. BOARD DIAGRAM 3-69 3-70 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 71 5-1. LED-L P.C. BOARD DIAGRAM 5-2. LED-R P.C. BOARD DIAGRAM 6. CD-KEY P.C. BOARD DIAGRAM 3-71 3-72 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 72 7. MIC/HP/PT P.C. BOARD DIAGRAM 8. WOOFER AMP P.C. BOARD DIAGRAM 3-73 3-74 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 73 3-75 3-76 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 74: Section 4. Cd Electrical Part

    (X802) (X802) O344MHz) at Pin 31 of IC807? Check IC801 Replace IC801 input/ output and control line. Refer to Function check Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 75: Usb Function

    Check IC801 Replace IC801 Display “NO FILE” PIN 116, 117) CHECK USB AUDIO FILE IN USB DEVICE (MP3, WMA FILE IS PLAYABLE) LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 76: Waveforms Of Major Check Point

    ADDRESS RESET 2. SERVO IC807 PIN30 CD-16M SERVOWAVEFORMS-FE,TE,FOD,RF 3. AUDIO PATH LRCK DATA CD_ I2S MUX_ I2S IC807 PIN34,35,36 IC801 PIN88,99,100 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 77 5. USB 4. TUNER USB_5V USB D+/ D- TUNER SPI CN803 PIN2,3,4 TUN800 PIN5,7,8,9 6. ADC LRCK DATA ADC I2S IC805 PIN11,12,10,9 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

  • Page 78: Dsp Schematic Diagram

    CD SCHEMATIC DIAGRAMS 1. DSP SCHEMATIC DIAGRAM 2008.01.25 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 79: Rf Servo Schematic Diagram

    2. RF SERVO SCHEMATIC DIAGRAM 2008.01.25 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 80 3. ADC SCHEMATIC DIAGRAM 2008.01.25 4-10 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 81 PRINTED CIRCUIT BOARD DIAGRAMS 1-1. CD P.C. BOARD DIAGRAM ( TOP VIEW ) 4-11 4-12 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...
  • Page 82 1-2. CD P.C. BOARD DIAGRAM ( BOTTOM VIEW ) 4-13 4-14 Copyright © 2008 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 83 4-15 4-16 LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes...

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