LG MCV902 Service Manual
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LG MCV902 Service Manual

Mini hi-fi system
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MINI Hi-Fi SYSTEM
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT, READ THE "SAFETY PRECAUTIONS"
IN THIS MANUAL.
MODEL : MCV902
(MCS902F, MCS902S, MCS902W, MCS902AW)
P/NO : AFN32840808
JANUARY, 2007

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  • Page 1 MINI Hi-Fi SYSTEM SERVICE MANUAL CAUTION BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS” IN THIS MANUAL. MODEL : MCV902 (MCS902F, MCS902S, MCS902W, MCS902AW) P/NO : AFN32840808 JANUARY, 2007...

  • Page 2: Table Of Contents

    CONTENTS SECTION 1 INTERNAL BLOCK DIAGRAM OF ICs ....3-12 1. HA12237F............3-12 GENERAL 2. NJW1190 ............3-13 3. AF330W20FT ...........3-13 SERVICING PRECAUTIONS ........1-2 4. AF350W01FT ...........3-15 • NOTES REGARDING HANDLING OF THE PICK-UP • NOTES REGARDING COMPACT DISC PLAYER REPAIRS WIRING DIAGRAM ............3-18 BLOCK DIAGRAM.............3-20 ESD PRECAUTIONS ...........1-4 LOCATION OF USERS CONTROLS......1-5...

  • Page 3: Servicing Precautions

    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. 2.

  • Page 4: 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 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: Location Of Users Controls

    16.AM/ FM ANTENNA TERMINAL • USER EQ button 17.AUX IN (AUXILIARY INPUT connector) • MP3 OPT (MP3 OPTIMIZER) button 18.VIDEO OUT connector • MULTI JOG 19.WOOFER SYSTEM connector (MCV902 model) MANUAL TUNING 20.SUB WOOFER SPEAKER TERMINAL CD SKIP ( (MCV902 model) CLOCK ADJUST...
  • Page 7 REMOTE CONTROL...

  • Page 8: Specifications

    (MW) Signal to noise ratio 30dB Frequency response 140 ~ 1800Hz Front : 270W + 270W (MCV902 Model) 250W + 250W (MCV502 Model) Output power Surround : 110W + 110W (MCV902 Model) [AMP] Subwoofer : 175W + 175W (MCV902 Model) T.H.D...
  • Page 9 MEMO...

  • Page 10: Exploded Views

    SECTION 2 EXPLODED VIEWS CABINET EXPLODED VIEW SVC purchase order caution MAIN board is array coming USB board. Purchase order board separately supply incomprehensible. Supply is possible in Location No A46 state in exploded views. MAIN FRONT SMPS...

  • Page 11: Tape Deck Mechanism Exploded View

    TAPE DECK MECHANISM EXPLODED VIEW 1. TAPE DECK MECHANISM (A/R & A/S : A/R DECK)

  • Page 12: Tape Deck Mechanism (A/R & A/S : A/S Deck)

    2. TAPE DECK MECHANISM (A/R & A/S : A/S DECK)

  • Page 13: Cd Mechanism Exploded View

    CD MECHANISM EXPLODED VIEW...

  • Page 14: Speaker Exploded View

    SPEAKER EXPLODED VIEW 1. MODEL : MCS902F 2-10...

  • Page 15: Model : Mcs902S

    2. MODEL : MCS902S 2-11 2-12...

  • Page 16: Model : Mcs902W

    3. MODEL : MCS902W 2-13 2-14...

  • Page 17: Model : Mcs902Aw

    4. MODEL : MCS902AW 2-15 2-16...

  • Page 18: Packing Accessory View

    PACKING ACCESSORY VIEW 2-17...

  • Page 19: Electrical Troubleshooting Guide

    SECTION 3 AUDIO PART ELECTRICAL ELECTRICAL TROUBLESHOOTING GUIDE 1. POWER (SMPS) CHECK AC CONNECT NO POWER LINE PATTERN THE OPEN LINE CHECK F901 FUSE REPLACE FUSE CHECK BD901 + TO LOW IMPEDANCE - PIN IMPEDANCE CHANGE ASSY CHECK C986 CHECK LINE SHORT VOLT(5.6V) CHECK CONNECTION CN902, CN903...

  • Page 20: P-Sens

    2. P-SENS P-SENS PART SMPS ASS'Y CN902 SMPS TROUBLESHOOTING CONSULT - -> 7PIN 5.1V CHECK MAIN PCB CN710 CN710 CONNECTION STATE CHECK 7PIN 5.1V CHECK MAIN PCB CN304 MAIN PCB PATTERN CUTTING 6PIN 5.1V CHECK AND SHORT CHECK FRONT PN304 35 PIN 5.1V CHECK IC304 INPUT VOLTAGE 5V OVER FRONT IC304(RESET IC) STATE CHECK AND OUTPUT VOLTAGE 4V...

  • Page 21: Micom (Ic302) Change

    4. MICOM (IC302) CHANGE MICOM (IC302) CHANGE P-SENS "P-SENS" TROUBLESHOOTING CHECK CONSULT "RESET" TR "Q302, Q303" IC302 Q302, Q303 CHANGE 10PIN CHECK(LOW STATE CHECK --> HIGH) IC302 VDD SMPS PN304 34PIN MAIN CN710 (19, 20, 59) PIN TROUBLESHOOTI +5.6V (MI) CHECK 6PIN CHECK VOLTAGE NG CONSULT...

  • Page 22: Muting Troubleshooting (Mute State)

    6. MUTING TROUBLESHOOTING (MUTE STATE) MUTING TROUBLESHOOTING (MUTE STATE) MICOM EXPEND IC(IC305) Q752(A102) IC302 57PIN HIGH STATE CHECK Emitter "HIGH" STATE CHECK EXPEND IC(IC305) Q752(A102) STATE CHECK FAULTY IS CHANGE Q752(A102) FAULTY IS CHANGE Q701, Q751(D1302) EACH PART TR CHANGE BASE "HIGH"...

  • Page 23: Function Mode Has No Sound (Njw1190) Ic601

    8. FUNCTION MODE HAS NO SOUND (NJW1190) IC601 TAPE IC201 INPUT DECK HEAD WIRE CHECK(HEAD INPUT) "A" CONNECTION STATE CHECK DECK 32, 39 "B" DECK 34, 37 IC502 10PIN IC502 2PIN/3PIN IC201 OUTPUT (PB MUTE) STATE CHECK (DATA/CLK) CHECK(5, 26PIN) CHECK IC502 16PIN VDD CHECK IC502 EXPEND IC CHANGE...
  • Page 24 JK601 SIGNAL INPUT CHECK IC601 5, 34PIN MAIN PCB PATTERN CHECK SIGNALINPUT CHECK IC601 (NJW1190) IC601 17, 22PIN TROUBLESHOOTING CONSULT OUTPUT SIGNAL CHECK AUX OUTPUT PN709 6, 8PIN SIGNAL CHECK and CD TROUBLESHOOTING CONSULT IC601 4, 35PIN MAIN PCB PATTERN CHECK SIGNAL INPUT CHECK IC601(NJW1190) IC601 17, 22PIN...
  • Page 25 TUNER TU101 2PIN TU101 3/5 CN701 2PIN "+12V" CHECK "+9V" VOLTAGE SIGNAL CHECK CHECK TU101 6, 7, 8, MICOM IC302 CHECK 9PIN CHECK (PLL-CE,PLL-DI, (PIN 73, 71, 70, 72) CLK, PLL-DO) TUNER MODULE CHANGE IC601 2, MAIN PCB PATTERN CHECK 37PIN SIGNAL INPUT CHECK IC601 17,...

  • Page 26: Ic601(Njw1190) Troublushooting

    9. IC601(NJW1190) TROUBLUSHOOTING IC601(NJW1190) TROUBLUSHOOTING IC601 24PIN SMPS VOLTAGE CHECK CONSULT VOLTAGE INPUT CHECK IC601 19, 20 SDA, SCA PULSE WAVE CHECK IC302 7, 72PIN CHECK (VOL UP, DOWN TURN CHECK) IC302 TROUBLESHOOTING FUNCTION INPUT IC601 CHANGE PORT SIGNAL CHECK (NJW1190 TROUBLESHOOTING) IC601 17, 22PIN WAVE OUTPUT CHECK IC601 OK...

  • Page 27: Amp Module Troubleshooting

    10. AMP MODULE TROUBLESHOOTING AMP MODULE TROUBLESHOOTING IC501 9PIN (AMP-PWR) EXPEND IC TROUBLESHOOTING CONSULT HIGH CHECK PN702 3PIN PROTECTION "HIGH" --> SMPS VOLTAGE "PROTECTION" CHECK AND AMP ON/OFF STATE CHECK (HIGH --> LOW) AMP MODULE CHECK : MOS FET BOTH ARE READ SHORT -->...

  • Page 28: Rec Check

    11. REC CHECK (Q201, Q202 ON : R276, R226 HIGH) IC601 21PIN VOLTAGE INPUT CHECK IC601 EACH INPUT TUNER 2, 37 TAPE 3, 36 REC INPUT CHECK CD 4, 35 AUX 5, 34PIN SIGNAL INPUT CHECK IC201 7, 24PIN INPUT LINE CHECK INPUT CHECK IF NO SIGNAL, IC201 10, 21PIN...

  • Page 29: Dubbing Check ("Normal Or Rec" // "High")

    12. DUBBING CHECK ("NORMAL OR REC" // "HIGH") IC601 7, 32 OUTPUT CHECK IC601 EACH INPUT TUNER 2, 37 REC INPUT CHECK TAPE 3, 36 CD 4, 35 AUX 5, 34PIN SIGNAL INPUT CHECK INPUT LINE CHECK IC201 7, 24PIN INPUT CHECK IC201 10, 21PIN OUTPUT CHECK 3-11...

  • Page 30: Internal Block Diagram Of Ics

    INTERNAL BLOCK DIAGRAM OF ICs 1. HA12237F 3-12...

  • Page 31: Njw1190

    2. NJW1190 3. AF330W20FT 3-1. PIN CONFIGURATION 3-13...
  • Page 32 3-2. BLOCK DIAGRAM 3-3. PIN DESCRIPTION 3-14...

  • Page 33: Af350W01Ft

    4. AF350W01FT 4-1. PIN CONFIGURATION 4-2. BLOCK DIAGRAM 3-15...
  • Page 34 4-3. PIN DESCRIPTION 3-16...
  • Page 35 MEMO 3-17...

  • Page 36: Wiring Diagram

    WIRING DIAGRAM 3-18 3-19...

  • Page 37: Block Diagram

    BLOCK DIAGRAM 3-20 3-21...

  • Page 38: Schematic Diagrams

    BE MODIFIED OR ALTERED WITHOUT PERMISSION FROM THE ACTUAL CIRCUIT USED. THIS WAY, 2. Voltages are DC-measured with a digital voltmeter FROM THE LG CORPORATION. ALL COMPONENTS IMPLEMENTATION OF THE LATEST SAFETY AND during Play mode. SHOULD...

  • Page 39: Sub Smps (Power) Schematic Diagram

    SCHEMATIC FOR EASY IDENTIFICATION. THIS CIRCUMSTANCES SHOULD THE ORIGINAL DESIGN CIRCUIT DIAGRAM MAY OCCASIONALLY DIFFER BE MODIFIED OR ALTERED WITHOUT PERMISSION FROM THE ACTUAL CIRCUIT USED. THIS WAY, FROM THE LG CORPORATION. ALL COMPONENTS IMPLEMENTATION OF THE LATEST SAFETY AND SHOULD REPLACED ONLY...

  • Page 40: Audio Main Schematic Diagram

    3. AUDIO MAIN SCHEMATIC DIAGRAM 3-26 3-27...

  • Page 41: Deck Schematic Diagram

    4. DECK SCHEMATIC DIAGRAM 3-28 3-29...

  • Page 42: Usb, Aux2 & Headphone Amp Schematic Diagram

    5. USB, AUX2 & HEADPHONE AMP SCHEMATIC DIAGRAM 3-30 3-31...

  • Page 43: I/O Jack Schematic Diagram

    6. I/O JACK SCHEMATIC DIAGRAM 3-32 3-33...

  • Page 44: Amp Schematic Diagram

    7. AMP SCHEMATIC DIAGRAM 3-34 3-35...

  • Page 45: Woofer Amp Schematic Diagram

    8. WOOFER AMP SCHEMATIC DIAGRAM 3-36 3-37...

  • Page 46: Front Schematic Diagram

    9. FRONT SCHEMATIC DIAGRAM 3-38 3-39...

  • Page 47: Printed Circuit Diagrams

    PRINTED CIRCUIT DIAGRAMS 1. MAIN P.C.BOARD 3-40 3-41...

  • Page 48: Smps (Power) P.c.board

    2. SMPS (POWER) P.C.BOARD 3. SUB SMPS (POWER) P.C.BOARD 3-42 3-43...

  • Page 49: Front P.c.board

    4. FRONT P.C.BOARD 3-44 3-45...

  • Page 50: Amp P.c.board

    5. AMP P.C.BOARD (TOP VIEW) (BOTTOM VIEW) 3-46 3-47...

  • Page 51: Woofer Amp P.c.board

    MEMO 6. WOOFER AMP P.C.BOARD 3-48 3-49...

  • Page 52: Cd Part Electrical

    SECTION 4 CD PART ELECTRICAL ELECTRICAL TROUBLESHOOTING GUIDE 1. CD PART TROUBLESHOOTING TURN ON CD OPEN CLOSE CHECK CONNECTOR CHECK (PN803, PN804) CHECK VOLTAGE CN806 PIN1 : 12V, PIN2 : 6.3V CHECH VOLTAGE PN805 PIN22 : CLOSE, PIN23 : OPEN CONNECTOR CHECK “READING”...
  • Page 53 1-1. OPEN CLOSE NG CONNECTOR LOCKING CHECK (PN803, PN804, PN814 ) CHECK POWER SUPPLY CIRCUIT (PN805, CN806) DEFECTIVE MAIN POEWR SUPPLY CN806 PIN1 : 12V, PIN2 : 6.3V PN805 PIN8 : +5V_AD CHECK VOLTAGE CHANGE OF OPEN CLOSE IC803 INPUT VOLTAGE DEFECTIVE MICOM PIN6 : 12V, PIN7 : 6.3V (PN805 PIN2 : BTL_MUTE, 23 : OPEN,...
  • Page 54 1-2. “READING” DISPLAY CHECK (= ONLY “CD” DISPLAY) CONNECTOR LOCKING CHECK (PN802, PN803, PN804, PN805, CN806 ) CHECK POWER SUPPLY PORT( PN805, CN806) DEFECTIVE CONNECTOR OR CN806 PIN1 : 12V, PIN2 : 6.3V, MAIN POWER SUPPLAY PIN4 : 5V PN805 PIN8 = 5V_AD CHECK VOLTAGE THE PIN 2 OF IC804...
  • Page 55 1-3. READING OK CHECK (= “NO DISC” DISPLAY) CONNECTOR LOCKING CHECK (PN801, PN802) CHECK PN802 DEFECTIVE PICKUP OR DOES SLED MOVE? PIN3, 4 (SL+, SL-) IC802 OR IC801 DOES CHECK PN801 DEFECTIVE PICKUP OR LENSE MOVE? PIN 13, 16 ( FA+, FA-) IC802 OR IC801 (= UP &...
  • Page 56 1-4. READING OK CHECK #A (= “NO DISC” DISPLAY) DOES SL+ WAVEFORM DOES SLIN APPEAR AT (IC802 WAVEFORM APPEAR AT DEFECTIVE IC801 PIN13 AND PN802 (IC802 PIN5) WAVEFORM PIN3) WAVEFORM #2 #2 SLED DRIVE SLED MOTOR WAVE WAVE DEFECTIVE IC802 DEFECTIVE PN802 CHECK PN802 CONNECTOR...
  • Page 57 1-6. READING OK CHECK #C (= “NO DISC” DISPLAY) IS 3.3V APPLIED TO IS ?V APPLIED PIN30, 36, 39, 41, 61, TO PIN10 OF PN801 DEFECTIVE IC804 68, 75 OF IC801 LASER SUPPLY RF IC SUPPLY VOLTAGE CHECK VOLTAGE CHECK IS 2.3V PIN18(LDO) OF IC801 DEFECTIVE IC801...
  • Page 58 1-7. READING OK CHECK #D (= “NO DISC” DISPLAY) DOES DOES SP+ WAVEFORM SPIN WAVEFORM APPEAR AT (IC802 PIN11 APPEAR AT (IC802 PIN6) DEFECTIVE IC801 AND PN802 PIN 5) WAVEFORM WAVEFORM #4 #4 SPINDLE MOTOR SPINDLE DRIVE DRIVE WAVE WAVE DEFECTIVE IC802 DEFECTIVE PN802 CHECK PN802...
  • Page 59 1-8. READING OK CHECK #E (= “NO DISC” DISPLAY) DOES DOES TA+ WAVEFORM TAIN- WAVEFORM APPEAR AT (IC802 PIN17 APPEAR AT (IC802 PIN22) DEFECTIVE IC801 ANDPN801 PIN14) WAVEFORM WAVEFORM #5 #5 TRACKING COIL TRACKING DRIVE DRIVEWAVE WAVE DEFECTIVE IC802 DEFECTIVE PN802 CHECK PN802 CONNECTOR CONNECTOR LINE...

  • Page 60: Usb Part Troubleshooting

    2. USB PART TROUBLESHOOTING TURN ON USB “CHECKING” OR CONNECTOR CHECK “USB” DISPLAY CHECK (PN805, CN806, PN810 ) CHECK POWER SUPPLY CIRCUIT(CN806) CHECK MICOM INTERFACE CIRCUIT(PN805) PIN13 : RX (IC805 PIN49 : TXD) PIN14 : TX (IC805 PIN33 : RXD) READING OK CHECK CHECK PN810 1PIN : 5V CHECK PN810 PIN2(D-), 3(D+)

  • Page 61: Waveforms Of Major Check Point

    WAVEFORMS OF MAJOR CHECK POINT #1.MICOM INTERFACE WAVEFORM #1.MICOM INTERFACE WAVEFORM (PN805 PIN26, 19, 3, 15) during power on (PN805 PIN26, 19, 3, 15) during normal play PIN26 : WRQ PIN26 : WRQ PIN19 : RESET PIN19 : RESET PIN3 : DI (IC801 PIN46 DATA OUT) PIN3 : DI (IC801 PIN46 DATA OUT) PIN15 : DO (IC801 PIN45 DATA IN) PIN15 : DO (IC801 PIN45 DATA IN)
  • Page 62 #2.SLED DRIVE AND MOTOR WAVEFORM #2.SLED DRIVE AND MOTOR WAVEFORM (IC802 PIN5, 13) when focus search (IC802 PIN5, 13) during normal play PIN5 : SLIN PIN5 : SLIN PIN13 : SL+ PIN13 : SL+ #3.FOCUS DRIVE AND MOTOR WAVEFORM #3.FOCUS DRIVE AND MOTOR WAVEFORM (IC802 PIN25, IC802 PIN16) (IC802 PIN25, IC802 PIN16) •...
  • Page 63 #4.SPINDLE DRIVE AND MOTOR WAVEFORM #5.TRACK DRIVE AND MOTOR WAVEFORM (IC802 PIN6, 11) when TOC reading (IC802 PIN22, IC802 PIN17) during normal play PIN22 : TAO PIN6 : SPIN PIN11 : SP+ PIN17 : TA+ #6.RF, FOCUS AND TRACKING ERROR WAVEFORM (IC801 PIN2, 10, 16) during normal play PIN2 : RFOUT PIN 16 : TE...

  • Page 64: Schematic Diagrams

    SCHEMATIC DIAGRAMS 1. CD SCHEMATIC DIAGRAM 4-13 4-14...

  • Page 65: Usb Schematic Diagram

    2. USB SCHEMATIC DIAGRAM 4-15 4-16...

  • Page 66: Printed Circuit Diagram

    PRINTED CIRCUIT DIAGRAM CD P.C.BOARD (TOP VIEW) (BOTTOM VIEW) 4-17 4-18...
  • Page 67 MEMO MEMO 4-19 4-20...

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