LG CM2760 Service Manual
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LG CM2760 Service Manual

Micro hi-fi audio
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Internal Use Only
Micro Hi-Fi Audio
SERVICE MANUAL
MODEL: CM2760
(CM2760, CMS2760F)
CAUTION
BEFORE SERVICING THE UNIT, READ THE "SAFETY PRECAUTIONS"
IN THIS MANUAL.
P/NO : AFN77360055
JANUARY, 2016

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  • Page 1 Internal Use Only Micro Hi-Fi Audio SERVICE MANUAL MODEL: CM2760 (CM2760, CMS2760F) CAUTION BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS” IN THIS MANUAL. P/NO : AFN77360055 JANUARY, 2016...
  • Page 2 CONTENTS SECTION 1 ..GENERAL SECTION 2 ..CABINET & MAIN CHASSIS SECTION 3 ..ELECTRICAL SECTION 4 ..REPLACEMENT PARTS LIST...

  • Page 3: Table Of Contents

    SECTION 1 SUMMARY CONTENTS SERVICING PRECAUTIONS ..........................1-3 ESD PRECAUTIONS ............................1-5 HIDDEN KEY MODE ............................1-6 SOFTWARE UPDATE GUIDE ..........................1-6 SPECIFICATIONS ............................. 1-7...

  • Page 4: Servicing Precautions

    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 5 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 6: 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 7: Hidden Key Mode

    HIDDEN KEY MODE HIDDEN AVAILABLE STATUS ENTRANCE KEY EXIT KEY DISPLAY MODE P1501290 Front Play OP0 FF Version Check POWER ON STATUS + RMC ‘Play’ RMC ‘PLAY’ for 1.5s Q1501290 for 5s EQCSFFFF Front Play EEPROM INITIAL POWER ON STATUS + RMC ‘|<<’...

  • Page 8: Specifications

    SPECIFICATIONS • GENERAL Power requirements Refer to the main label. Power consumption Refer to the main label. Networked standby : 0.5 W (If all network ports are activated.) Dimensions (W x H x D) Approx. 170 mm x 230 mm x 276 mm Net Weight Approx.
  • Page 10 SECTION 2 CABINET & MAIN CHASSIS CONTENTS EXPLODED VIEWS ............................2-3 1. CABINET AND MAIN FRAME SECTION ....................2-3 2. PACKING ACCESSORY SECTION ......................2-7 3. SPEAKER SECTION ..........................2-8...

  • Page 12: Exploded Views

    EXPLODED VIEWS NOTES) THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL 1. CABINET AND MAIN FRAME SECTION TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. CABLE3 CABLE5 CABLE4 MAIN CABLE1 PORTABLE CABLE2 CABLE6 CABLE8 CABLE7...

  • Page 14: Packing Accessory Section

    2. PACKING ACCESSORY SECTION Owner’s manual Batteries Remote control 803T Packing 803B Packing 802 Box...

  • Page 15: Speaker Section

    3. SPEAKER SECTION A60L A60R...
  • Page 16 SECTION 3 ELECTRICAL CONTENTS ONE POINT REPAIR GUIDE ..........................3-2 1. NO POWER PROBLEM ......................... 3-2 2. SPEAKER NO AUDIO OUTPUT ......................3-3 3. USB NO DETECT ........................... 3-4 4. PROTECTION ............................3-5 ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART ..............3-8 1.

  • Page 17: One Point Repair Guide

    ONE POINT REPAIR GUIDE 1. NO POWER PROBLEM No power problem occurs when you power on the unit. 1-1. NO POWER 1-1-1. Solution Replace X201, IC200, IC202. 1-1-2. How to troubleshoot (Countermeasure) 1) Check X201(Crystal).   If it does not oscillate, replace X201. 2) Check IC200(Reset IC).

  • Page 18: Speaker No Audio Output

    ONE POINT REPAIR GUIDE 2. SPEAKER NO AUDIO OUTPUT No audio output problem occurs when you power on the unit. 2-1. NO SOUND 2-1-1. Solution Reassemble AMP IC heat-sink, replace IC202. 2-1-2. How to troubleshoot (Countermeasure) 1) Reassemble AMP IC heat-sink (heat-sink screw must be assembled tightly). 2) Still NG, please check Q409, Q407, Q408 part out, if it is not appear 12 V.

  • Page 19: Usb No Detect

    ONE POINT REPAIR GUIDE 3. USB NO DETECT When USB insert, USB no detect on the unit. 3-1. NO DETECT 3-1-1. Solution Replace IC205. 3-1-2. How to troubleshoot (Countermeasure) 1) Please check IC205.   pin1 : 5 V 2) If it is not OK, replace IC205. 3-1-3.

  • Page 20: Protection

    ONE POINT REPAIR GUIDE 4. PROTECTION 4-1. D(DC) PROTECTION 4-1-1. Solution Replace IC301(AMP IC) on MAIN board. 4-1-2. How to troubleshoot (Countermeasure) 1) Press the power button, the display is normal, no sound output. (D Protection or S Protection) 2) Check DC Voltage of speaker out Front Left channel + & -(JK300 pin2, 1), Front Right channel + & - (JK300 pin4, 3).
  • Page 21 ONE POINT REPAIR GUIDE PROTECTION 4-2. S(SHUT DOWN) PROTECTION 4-2-1. Solution Replace IC301(AMP IC) on MAIN board. 4-2-2. How to troubleshoot (Countermeasure) 1) Press the power button, the display is normal, no sound output. (D Protection or S Protection) 2) Check PVDD Voltage. (27 V) - If PVDD abnormal Voltage, Refer to SMPS Board repair guide.
  • Page 22 ONE POINT REPAIR GUIDE PROTECTION 4-3. B(BURNT) PROTECTION 4-3-1. Solution Replace IC301(AMP IC) on MAIN board. 4-3-2. How to troubleshoot (Countermeasure) 1) Press the power button, the display is normal, no sound output. (B Protection) 2) Check Voltage 3.3 V of AMP_Protect signal. (collector Q303) 3) If collector Q303 is low(0 V), Replace IC301(AMP IC) on MAIN board.

  • Page 23: Electrical Troubleshooting Guide Of Audio Part

    ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART 1. SMPS POWER CIRCUIT No 27 V F900 normal? Replace F900 (same fuse). NTC900 normal? Replace NTC900. BD900 normal? Replace BD900. Is the Vcc (12 V~13 V) supplied to IC901 normal? IC901 pin5? The Main part IC400, IC401 Check or replace IC901.
  • Page 24 ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART No VCC 3.3 V Check IC400 pin4 Check IC400. voltage 5 V. Check D405 anode Check Q401. voltage 5 V. IC401 normal? Replace IC401. Check VCC33 network, the device a short circuit will cause no output. No 12 V Check Q407 collector Check Q407.

  • Page 25: Fld Display Check

    ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART 2. FLD DISPLAY CHECK FLD display check Check Refer to CN500 pin3, 11 Power part troubleshooting. voltage. Check VFD PCB Check T500, L500, Q500, Q501, F+, F- both terminals: Replace the related part. D501 part circuit. over 3.7 V.

  • Page 26: Touch Pad Check

    ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART 3. TOUCH PAD CHECK Touch pad check CN600 pin2 Check IC600 pin5 Refer to 3.3 V. 3.3 V. Power part troubleshooting. Check Check IC600 R652, C603, IC600 pin8:SDA, Replace the related part. part circuit. pin9:SCL.

  • Page 27: Pwm Modulation Part

    ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART 4. PWM MODULATION PART PWM modulation part check Check Refer to IC300(TAS5538) VDD Power Power part troubleshooting. (pin9, 14, 35, 50). Check Check IC300(TAS5538) IC300(TAS5538) pin11 CLK Replace the related part. pin11 CLK correlation network. input.

  • Page 28: Power Amp Part Check

    ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART 5. POWER AMP PART CHECK Power AMP part check Refer to Power part troubleshooting. The Main power of 27 V. Check input power of IC301 pin41, 40, 35, 32, 27, 26. Check Check resistance power IC301 pin1, 22, 23, 44: IC301: R301, R335, R336, R300.

  • Page 29: Aux Function Check

    ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART 6. AUX FUNCTION CHECK AUX function check Check whether CN500 contacts or not. Check Check IC302 FB308, FB309, R348, R338, Replace the related part. (CD4052) pin1, 12 input C362, C374. waveform. Check PHONE JACK JK500, CN502.

  • Page 30: Tuner Function Check

    ELECTRICAL TROUBLESHOOTING GUIDE OF AUDIO PART 7. TUNER FUNCTION CHECK Tuner function check Check Refer to Tuner IC304 pin11 5 V, Power part troubleshooting pin10 3.3 V. Check Check X300 Replace the related part. IC304 pin13, 14 input (32.768 kHz). waveform.

  • Page 31: Electrical Troubleshooting Guide Of Cd Part

    ELECTRICAL TROUBLESHOOTING GUIDE OF CD PART 1. CD PART Turn on CD. Check Check connector CN102. Open/ Close. Check voltage Refer to IC101 pin8, 19: 5 V. Power part troubleshooting Check CN102 pin3: Open, pin1: Close. Check connector DISC reading is OK? CN101, CN102, CN100.

  • Page 32: Open/ Close Ng

    ELECTRICAL TROUBLESHOOTING GUIDE OF CD PART 2. OPEN/ CLOSE NG Check connector locking. (CN102) Check Defective Main power supply. voltage IC101(AM5888) pin8, 19: 5 V. Check voltage IC101(AM5888) Defective IC101. pin9: MOT-, pin10: MOT+. Defective mechanism. 3. “ READING ” DISPLAY CHECK (= ONLY “CD” DISPLAY) Check connector locking.

  • Page 33: Reading Ok Check (= "No Disc" Display)

    ELECTRICAL TROUBLESHOOTING GUIDE OF CD PART 4. READING OK CHECK (= “NO DISC” DISPLAY) Check connector locking. (CN100, CN101) Check CN101 Defective Does sled move? pin3, 4 (SL+, SL-). pick-up or IC101 or IC100. Does lense move? Check CN100 Defective (= Up &...
  • Page 34 ELECTRICAL TROUBLESHOOTING GUIDE OF CD PART 4-1. READING OK CHECK #A (= “NO DISC” DISPLAY) Does Does SL+ SLIN waveform waveform appear at (IC101 pin11 Defective IC100. appear at (IC100 pin4) & IC100 pin15) waveform#2 waveform #2 sled drive sled motor Wave. wave Defective IC101.
  • Page 35 ELECTRICAL TROUBLESHOOTING GUIDE OF CD PART 4-3. READING OK CHECK #C (= “NO DISC” DISPLAY) Is 3.3 V Is 3.3 V applied applied to pin10 of CN100 laser To pin9, 30, 39, 1, 47 of IC100 RF IC supply voltage check. supply voltage check.
  • Page 36 ELECTRICAL TROUBLESHOOTING GUIDE OF CD PART 4-5. READING OK CHECK #E (= “NO DISC” DISPLAY) Does Does T+ VINTK waveform waveform appear at (IC101 pin15) Defective IC100. appear at (IC100 pin14) waveform #5 waveform#5 tracking tracking drive coil drive wave. wave.

  • Page 37: Usb Part

    ELECTRICAL TROUBLESHOOTING GUIDE OF CD PART 5. USB PART Turn on USB Check Check connector Check IC205 pin1. “CHECKING” or “USB” (CN202 pin5, 66: 5.5 V) display Check RB501 Check RB501 and CN202 pin1: 5.5 V. Line connector. Check JK501 pin5, 6: 5 V.

  • Page 38: Waveforms Of Major Check Point

    WAVEFORMS OF MAJOR CHECK POINT #1. MICOM INTERFACE WAVEFORM #1. MICOM INTERFACE WAVEFORM (IC100 pin19, 20, 30, 34) DURING (IC100 pin19, 20, 30, 34) DURING POWER ON NORMAL PLAY pin20: CD_RW pin20: CD_RW pin30: RESET pin30: RESET pin34: DI (IC100 pin46 DATA OUT) pin34: DI (IC100 pin46 DATA OUT) pin19: DO (IC100 pin45 DATA IN) pin19: DO (IC100 pin45 DATA IN)
  • Page 39 #2. SLED DRIVE AND MOTOR WAVEFORM #2. SLED DRIVE AND MOTOR WAVEFORM (IC101 pin4, 11) WHEN (IC101 pin4, 11) DURING FOCUS SEARCH NORMAL PLAY pin4: SLIN pin4: SLIN pin11: SL+ pin11: SL+ 3-24...
  • Page 40 #3. FOCUS DRIVE AND MOTOR WAVEFORM #3. FOCUS DRIVE AND MOTOR WAVEFORM (IC401 pin1, 14) (IC401 pin1, 14) • WHEN FOCUS SEARCH FAILED OR • THERE IS DISC ON TRAY AND FOCUS THERE IS NO DISC ON TRAY SEARCH SUCCESS pin1: VINFC pin1: VINFC pin14: F+...
  • Page 41 #4. SPINDLE DRIVE AND MOTOR WAVEFORM #5. TRACK DRIVE AND MOTOR WAVEFORM (IC101 pin17, 23) WHEN TOC READING (IC101 pin16, 26) DURING NORMAL PLAY pin26: TAO pin23: SPIN pin16: TA+ pin17: SP+ 3-26...
  • Page 42 #6. RF, FOCUS AND TRACKING ERROR WAVEFORM #7. AUDIO PART (I2S) WAVEFORM (IC100 pin61, 62, 63) DURING NORMAL PLAY pin63: RFOUT pin62: TE pin61: RFMON(FE) 13 15 14 17 18 19 3-27...
  • Page 43 3-28...

  • Page 44: Wiring Diagram

    WIRING DIAGRAM 3-29 3-30...

  • Page 45: Block Diagram

    BLOCK DIAGRAM CD DI/DO A; B; C; D; E; F CD Busy Crystal DA11 CD Reset 32.768 kHz CD Mute Servo BU9546 Crystal 24 MHz CD IIS Motor Driver SP; SL; Load; F AM5888 SPK OUT L Channel Series Flash L/R=80 W x 2 Power AMP L/R PWM...

  • Page 46: Circuit Voltage Chart

    CIRCUIT VOLTAGE CHART 1. CONNECTORS VOLTAGE INPUT VOLTAGE: 200-264 V / 50-60 Hz Voltage Voltage Voltage Voltage Connector No. Pin No. Pin Name Connector No. Pin No. Pin Name Spec. Stress V Spec. Stress V DEBUG 0~3.3 V 3.3 V Main Board CN203 Vref...

  • Page 47: Printed Circuit Board Diagrams

    PRINTED CIRCUIT BOARD DIAGRAMS NOTE) Warning Parts that are critical with respect to risk 1. MAIN P. C. BOARD of fire or electrical shock. (TOP VIEW) (BOTTOM VIEW) 3-49 3-50...

  • Page 48: Touch P. C. Board

    2. TOUCH P. C. BOARD (TOP VIEW) (BOTTOM VIEW) 3. VFD P. C. BOARD (TOP VIEW) (BOTTOM VIEW) 3-51 3-52...

  • Page 49: Usb P. C. Board

    4. USB P. C. BOARD (TOP VIEW) (BOTTOM VIEW) 5. PORTABLE P. C. BOARD (TOP VIEW) (BOTTOM VIEW) 3-53 3-54...
  • Page 50 3-55 3-56...

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