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LG LM-M540 Service Manual

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❍ SECTION 1. GENERAL
• SERVICING PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
• ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
❍ SECTION 2. ELECTRICAL SECTION
• ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
• ELECTRICAL TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
• INTERNAL BLOCK DIAGRAM of ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21
• BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31
• SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33
• WIREING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-45
• PRINTED CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-47
❍ SECTION 3. EXPLODED VIEWS
• CABINET AND MAIN FRAME SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
• TAPE DECK MECHANISM (A/R & A/S : LEFT A/S DECK) . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
• TAPE DECK MECHANISM (A/R & A/S : RIGHT A/R DECK) . . . . . . . . . . . . . . . . . . . . . . . . . .3-5
• CD MECHANISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
❍ SECTION 4. SPEAKER PART
• SPEAKER PART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1
❍ SECTION 5. REPLACEMENT PARTS LIST
• REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1
[CONTENTS]
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Summary of Contents for LG LM-M540

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

  • Page 2: 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 3: Notes Regarding Compact Disc Player Repairs

    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 4: 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 5: Section 2. Electrical

    SECTION 2. ELECTRICAL ❏ ADJUSTMENTS This set has been aligned at the factory and normally will not require further adjustment. As a result, it is not recommended that any attempt is made to modificate any circuit. If any parts are replaced or if any- one tampers with the adjustment, realignment may be necessary.

  • Page 6: Vkk Check

    ❏ ELECTRICAL TROUBLESHOOTING GUIDE I AUDIO PART P-SENS PART CHECK ZD 901(5V) Voltage check Half-wave rectification wave form check D713 Replacement IC301 26PIN PATTERN Check R783 check, then ZD901 replacement VKK CHECK CN302 28pin DC -33V check ZD902 -33V check ZD902 replacement IC301 51PIN check Q903 turn on check...

  • Page 7: Power Check

    POWER CHECK Every kinds of Fuse check Fuse replace C901(+), C902(-) DC power output check CN901 1, 5 AC voltage output check Power supply Ass’y check and transformer replacent D901 replacement C903(+) DC power output check CN901, 9, 10 pin DC power output check Power supply Ass’y check and transformer replacent D902, D903, D904, D905 (1SR35)
  • Page 8 Muting circuit Troubleshooting (if MUTE) Q702(A102) Base “LOW” Q702 Base and GND operation status check Q701, Q751(IC302) Base “LOW” check MUTE No sound IC 601 12, 27 PIN Output check Refer to IC601(TDA7468D) IC specification IC701 input check (14PIN) Refer Muting troubleshooting IC701 output check (6PIN) IC701 12PIN (over 2V) check and power supply circuit check...
  • Page 9 SPK Relay Troubleshooting D704(+) 12V check Refer power check Q704 Collector “Low” check Q704 Base “High” Refer IC501(BU2090) Troubleshooting Output check Q704 Replacement RELAY Replacement (RY701) normal operation Specific FUNCTION MODE has no sound TAPE IC601 3,26 PIN signal input check Refer IC202 Troubleshooting IC601 5, 24 PIN signal input check JK600 signal input check...
  • Page 10 IC601 6,23 PIN signal input check CN513 1,3 PIN signal check and refer to CD Troubleshooting TUNER IC601 4, 25 PIN signal input check Refer TUNERMODULE IC602 2PIN check Refer to IC404 Troubleshooting IC301 Troubleshooting C301 17, 46, 72, 90 power applied check Refer to power supply check IC301 26PIN 5V applied check P-SENS terminal check...
  • Page 11 IC501 Troubleshooting IC501 16PIN power applied check Refer to power supply check IC501 2, 3 PIN CLK Data check IC301 3,4 PIN data check (When switched to CD, TAPE Function) Refer to IC301 Troubleshooting CONTROL function check IC501 replace Pattern check between IC301 and IC501 normal IC601(TDA7468D) Troubleshooting IC601 1PIN power applied check...
  • Page 12 IC701, IC751 Troubleshooting 3PIN signal input check Refer to Muting circuit 8, 15Pin(-), 7, 13Pin(+) voltage check Refer to power supply check 14 Pin signal output check 9, 10PIN power check (over 5V) PLAY check IC202 18Pin VCC power applied Refer to power supply check IC202 5,20 Pin signal output check Deck Mecha operation performance check...
  • Page 13 Rec check (Q252, Q202 ON : R273, R223 High) IC202 11,14PIN signal input check Q253, Q203 Base "Low" check Refer to IC203 Troubleshooting IC202 9,16 Pin signal input check Q253,Q203 replacement IC202 18Pin VCC voltage check IC201 6(12V), 4 Pin High check Power check, IC203 Troubleshooting check L203 2,3PIN oscilation check C236(+) power supply check...
  • Page 14 I CD PART TURN ON CD OPEN CLOSE CHECK CONNECTOR CHECK ( PN808,PN807 ) CHECK POWER SUPPLY CIRCUIT( PN808 ) CHECK MICOM INTERFACE CIRCUIT( PN807 ) “ READING ” DISPLAY CHECK CONNECTOR CHECK ( PN808,PN807,PN802,PN801 ) CHECK MICOM INTERFACE CIRCUIT( PN807 ) READING OK CHECK CONNECTOR CHECK(PN801,PN802) CHECK PICKUP MOVEMENT...

  • Page 15: Open Close Ng

    OPEN CLOSE NG CONNECTOR LOCKING CHECK ( PN808,PN807 ) CHECK POWER SUPPLY CIRCUIT( PN808 ,PN807) DEFECTIVE MAIN PN808 PIN 5 = 6.2V, PIN 7 = 5V POEWR SUPPLY PN807 PIN 1 = 5V DEFECTIVE MICOM CHECK VOLTAGE CHANGE OF OPEN CLOSE , AND BTLMUTE VOLTAGE(= 5V) (PN807 PIN 20:OPEN, 19:CLOSE, 4:BTLMUTE) CHECK VOLTAGE CHANGE LO+, LO- OF IC803...

  • Page 16: Reading Display Check (= Only "Cd "Display)

    READING DISPLAY CHECK (= ONLY “CD “DISPLAY) CONNECTOR LOCKING CHECK (PN808,PN807,PN802,PN801 ) CHECK POWER SUPPLY DEFECTIVE CONNECTOR OR PORT( PN808 ,PN807) MAIN POWER SUPPLAY PN808 PIN 5 = 6.2V, PIN 7 = 5V PN807 PIN 1 = 5V CHECK VOLTAGE THE PIN 2 OF IC805 DEFECTIVE IC805 IC805 PIN2 : 3.3V CHECK RESET SIGNAL OF PN807...
  • Page 17 READING OK CHECK (= “NO DISC” DISPLAY) CONNECTOR LOCKING CHECK(PN801,PN802) DOES SLED MOVE ? A A A A CHECK PN802 PIN 3,4( SL+,SL-) DEFECTIVE PICKUP OR IC803 OR IC801 OR IC802 DOES LENSE MOVE ? (= UP & DOWN) B B B B DEFECTIVE PICKUP OR CHECK PN801 PIN 13,16 IC803 OR IC801...
  • Page 18 READING OK CHECK #A (= “NO DISC” DISPLAY) A A A A DOES SL+ WAVEFORM APPEAR AT ( IC803 PIN14 AND PN802 PIN3) WAVEFORM #2 SLED MOTOR WAVE DOES SLIN WAVEFORM APPEAR AT DEFECTIVE IC801 ( IC803 PIN 5) WAVEFORM #2 SLED DRIVE WAVE DEFECTIVE IC803 DEFECTIVE PN802...
  • Page 19 READING OK CHECK #B (= “NO DISC” DISPLAY) B B B B DOES FA+ WAVEFORM APPEAR AT ( IC803 PIN15 AND PN801 PIN16) WAVEFORM #3 FOCUS COIL DRIVE WAVE DOES FAIN- WAVEFORM APPEAR AT DEFECTIVE IC801 ( IC803 PIN 26) WAVEFORM #3 FOCUS DRIVE WAVE DEFECTIVE IC803...
  • Page 20 READING OK CHECK #C (= “NO DISC” DISPLA) C C C C C C C C IS ?V APPLIED TO PIN10 OF PN801 LASER SUPPLY VOLTAGE CHECK IS 3.3 V APPLIED TO PIN3 OF IC802 RF IC SUPPLY VOLTAGE DEFECTIVE IC805 CHECK IS 2.0 V PIN2 OF IC802 DEFECTIVE IC802...
  • Page 21 READING OK CHECK #D (= “NO DISC” DISPLAY) D D D D DOES SP+ WAVEFORM APPEAR AT ( IC803 PIN12 AND PN802 PIN6)WAVE- FORM #4 SPINDLE MOTOR DRIVE WAVE DOES SPIN WAVEFORM APPEAR AT( IC803 PIN 6) DEFECTIVE IC801 WAVEFORM #4 SPINDLE DRIVE WAVE DEFECTIVE IC803 DEFECTIVE PN802...
  • Page 22 READING OK CHECK #E (= “NO DISC” DISPLAY) E E E E DOES TA+ WAVEFORM APPEAR AT ( IC803 PIN17 AND PN801 PIN15) WAVEFORM #5 TRACKING COIL DRIVE WAVE DOES TAIN- WAVEFORM APPEAR AT DEFECTIVE IC801 ( IC803 PIN 23) WAVEFORM #5 TRACKING DRIVE WAVE DEFECTIVE IC803...
  • Page 23 WAVEFORMS OF MAKOR CHECK POINT - 2-19 -...
  • Page 24 #4. SPINDLE DRIVE AND MOTOR WAVEFORM #5. TRACK DRIVE AND MOTOR WAVEFORM (IC503 pin6, 1 2) when TOC reading (TP560, IC503 pin23) during normal play #6. RF, TRACKING AND FOCUS ERROR WAVEFORM (IC502 pin8, 2 1 , 23) during normal play - 2-20 -...

  • Page 25: Pin Configuration

    ❏ INTERNAL BLOCK DIAGRAM of ICs • NJM2706M (IC1) BLOCK DIAGRAM PIN CONFIGURATION - 2-21 -...
  • Page 26 • BA3126N (IC201) BLOCK DIAGRAM PIN CONFIGURATION - 2-22 -...
  • Page 27 • KIA6289N (IC202) BLOCK DIAGRAM - 2-23 -...
  • Page 28 - 2-24 -...
  • Page 29 - 2-25 -...
  • Page 30 - 2-26 -...
  • Page 31 • TDA7468D (IC601) BLOCK DIAGRAM - 2-27 -...
  • Page 32 PIN CONFIGURATION - 2-28 -...
  • Page 33 • STK403-070 (IC701) BLOCK DIAGRAM - 2-29 -...
  • Page 34 - 2-30 -...

  • Page 35: Block Diagram

    ❏ BLOCK DIAGRAM 2-31 2-32...

  • Page 36: Main Schematic Diagram

    ❏ SCHEMATIC DIAGRAMS • MAIN SCHEMATIC DIAGRAM 2-33 2-34...

  • Page 37: Schematic Diagrams

    • MAIN-1 SCHEMATIC DIAGRAM 2-35 2-36...

  • Page 38: Deck Schematic Diagram

    • DECK SCHEMATIC DIAGRAM 2-37 2-38...

  • Page 39: Front Schematic Diagram

    • FRONT SCHEMATIC DIAGRAM 2-39 2-40...
  • Page 40 • CDP SCHEMATIC DIAGRAM 2-41 2-42...

  • Page 41: Power Schematic Diagram

    • POWER SCHEMATIC DIAGRAM NOTE: Warning NOTE: Parts that are shaded are critical With respect 1. Shaded(I) parts are critical for safety.Replace only to risk of fire or electrical shock. with specified part number. 2. Voltages are DC-measured with a digital voltmefer during Play mode.
  • Page 42 ❏ WIRING DIAGRAM CN901 PN901 PN401 2-45 2-46...

  • Page 43: Printed Circuit Diagrams

    ❏ PRINTED CIRCUIT DIAGRAMS • MAIN P.C. BOARD (COMPONENT SIDE) 2-47 2-48...
  • Page 44 • MAIN P.C. BOARD (SOLDER SIDE) 2-49 2-50...

  • Page 45: Front P.c. Board

    • FRONT P.C. BOARD 2-51 2-52...
  • Page 46 • POWER P.C. BOARD (COMPONENT SIDE) 2-53 2-54...
  • Page 47 • POWER P.C. BOARD (SOLDER SIDE) 2-55 2-56...

  • Page 48: Section 3. Exploded Views

    SECTION 3. EXPLODED VIEWS • CABINET AND MAIN FRAME SECTION MECHA Ass'y...

  • Page 49: Tape Deck Mechanism (A/R & A/S : Left A/S Deck)

    • TAPE DECK MECHANISM (A/R & A/S : LEFT A/S DECK) LOCA. NO. LG PART NO. DESCRIPTION SPECIFICATION 6720AG0002C DECK,AUDIO CWM42FR47 TOKYO PIGEON L-DOUBL 6768R-PP03A DECK MECHANISM PARTS 33-160-4309 PIGEON PRESS CASSE 6768R-GP03B DECK MECHANISM PARTS 50-222-4578 PIGEON GEAR IDLER...

  • Page 50: Tape Deck Mechanism (A/R & A/S : Right A/R Deck)

    • TAPE DECK MECHANISM (A/R & A/S : RIGHT A/R DECK) LOCA. NO. LG PART NO. DESCRIPTION SPECIFICATION 6720AG0002C DECK,AUDIO CWM42FR47 TOKYO PIGEON L-DOUBL 6768R-UP03D DECK MECHANISM PARTS 50-093-4895 PIGEON PWB UNIT CW 6768R-BP03D DECK MECHANISM PARTS 02-083-4254 PIGEON BELT/FELT C...

  • Page 51: Cd Mechanism

    • CD MECHANISM LOCA.NO. PART NO DESCRIPTION SPECIFICATION 4405RBE004C MECHANISM ASSEMBLY CDM-H1503 3 CD CHANGER 3041RB0002C BASE ASSEMBLY PU(SPRING DAMPER) 6717RCA001A PICK UP ASSY KSM-213VSCM SONY FRONT LOADING 3390RB0002A TRAY DISC(CDM-H1503) 4470RB0005A GEAR TRAY (CDM-H1503) 4681RBA001A MOTOR ASSEMBLY TRAY (CDM-H1503) 6871RF9211A PWB(PCB) ASSEMBLY,FRONT 1503 T/D SENSOR...
  • Page 52 3-10...

  • Page 53: Section 4. Speaker Section

    SECTION 4. SPEAKER SECTION ❏ MODEL: LMS-M540 LEFT RIGHT LEFT RIGHT LOCA.NO PART NO. DESCRIPTION SPECIFICATION 3720RMF104A PANEL,FRONT SPK LMS-M540 MOLD FRONT PANEL 3720RMF111A PANEL,FRONT SPK LMS-M540 MOLD PANEL FRONT 3530RMM019A GRILLE LMS-M540 PRESS METAL GRILLE WF 3530RMM020A GRILLE LMS-M540 PRESS METAL GRILLE 1. 353M050M SCREW,DRAWING + 2 D3.5 L10.0 MSWR3/FZY...
  • Page 54 - 4-2 -...

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