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LG LM-M1040A Service Manual

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P/N : 3829RAT113R
OCTOBER, 2004
MINI HI-FI SYSTEM
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT, READ THE "SAFETY PRECAUTIONS" IN THIS MANUAL.
MODEL: LM-M1040A, LMS-M1040

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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: LM-M1040A, LMS-M1040 P/N : 3829RAT113R OCTOBER, 2004...
  • Page 2 [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

    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 - 1-5 -...
  • Page 7 MEMO - 1-6 -...

  • Page 8: 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 9 ❏ ELECTRICAL TROUBLESHOOTING GUIDE I AUDIO PART P-SENS PART Does +6V appear at pin7 of PN514 Check the waveform of D913(+). Replacement D913 Check the pattern of IC301 Pin 26. Check R943 and replace ZD901. VKK PART Does DC-33V appear at PN514 pin3. Dose -33V appear at ZD902(-) ZD902 replacement Check the voltage of IC301 pin51...

  • Page 10: Smps Circuit

    SMPS CIRCUIT Check the Fuse Check the DC Output of C942, C944 Check the D940, D941 Replacement the IC901 Replace the D940, D941 Check the DC output of C755, C956, C957 (12V) (6.2V) (-32V) Check the DC output of IC941, C958 Replace the D947, D956, D955 Check the output of C949(5V) Replace the F940.
  • Page 11 Muting circuit Troubleshooting (if MUTE) Check pin2 of troubleshooting Does “Low” appear at Q602 “B” Q701, Q751(IC302) Base “LOW” check Check the connector of Q602 “B” & GND MUTE Audio abnormal Check the output of IC601 pin24, 25 Refer to “IC601 Troubleshooting”. Check pin 6, 10 of IC401 Refer to “IC401 Troubleshooting”.

  • Page 12: Function Mode Audio Abnormal

    FUNCTION MODE AUDIO ABNORMAL TAPE Check the signal input of IC601 pin28, 37 Refer to IC601 troubleshooting Refer IC14 Troubleshooting Check the signal input of IC601, pin29, 36 Refer to IC601 troubleshooting Check the signal input of JK600 Check the signal input of IC601 pin31, 34 Refer to IC601 troubleshooting Check the signal of CN513 pin1, 3 or Refer to CD Troubleshooting TUNER...
  • Page 13 IC301 Troubleshooting Check the power supplying IC301 pin17, 46, 90? Refer to power circuit Troubleshooting. Check the 5V of IC301 pin26 Check the P-SENS Check the oscillation of X301. Replace X301 Check the “Low”©“High” of IC301 pin17 when power supplied Check the RESET circuit Replace IC301 IC501 Troubleshooting...
  • Page 14 IC601 Troubleshooting Check the power supplied to IC601 pin39 Refer to “power circuit troubleshooting”. Check the Pulse waveform of IC601 pin21, 22(VOL DIAL) Check the IC301 pin76, 75, 5, 10 Refer the “IC301 IC601 7,22 Pin waveform output check Troubleshooting” Replace the IC601 Check the PATTERN of MICOM(82, 83) &...
  • Page 15 PLAY check Check the VCC supply to IC202 pin18 Refer to power circuit Troubleshooting. Check the signal output of IC202 pin5, 20 Check the Deck Mechanism Replace the Deck Mechanism Check the Muting circuit Replacement IC202 Dubbing check ("NORMAL or REC"//"HIGH") Q252, 202 "OFF"//"ON"...
  • Page 16 REC (Q252, Q202 ON : R273, R223 High) Check signal supplied to IC202 pin11, 14? Check the “Low” of Q253 Q203 “B” Refer to IC203 Troubleshooting Chek the output of IC202 pin9, 16 Replacement Q253,Q203 Check the Vcc power of IC202 pin18 Check the IC201 pin6:12V and pin 4: High Check the power or Refer to IC203 Troubleshooting Check the oscillation of L203 pin2, 3...
  • Page 17 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 18: 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 19: 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 20 READING OK CHECK (= “NO DISC” DISPLAY) CONNECTOR LOCKING CHECK(PN801,PN802) DOES SLED MOVE ? CHECK PN802 PIN 3,4( SL+,SL-) DEFECTIVE PICKUP OR IC803 OR IC801 OR IC802 DOES LENSE MOVE ? (= UP & DOWN) DEFECTIVE PICKUP OR CHECK PN801 PIN 13,16 IC803 OR IC801 ( FA-, FA+) DOES LASER LIGHT ?
  • Page 21 READING OK CHECK #A (= “NO DISC” DISPLAY) 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 CHECK PN802 CONNECTOR LINE...
  • Page 22 READING OK CHECK #B (= “NO DISC” DISPLAY) 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 DEFECTIVE PN801 CHECK PN801 CONNECTOR LINE...
  • Page 23 READING OK CHECK #C (= “NO DISC” DISPLA) 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 LASER CONTROL VOLTAGE CHECK...
  • Page 24 READING OK CHECK #D (= “NO DISC” DISPLAY) 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 CHECK PN802 CONNECTOR LINE...
  • Page 25 READING OK CHECK #E (= “NO DISC” DISPLAY) 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 DEFECTIVE PN802 CHECK PN802 CONNECTOR LINE...
  • Page 26 • WAVEFORMS OF MAKOR CHECK POINT - 2-19 -...

  • Page 27: Spindle Drive And Motor Waveform

    #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 28: Internal Block Diagram Of Ics

    ❏ INTERNAL BLOCK DIAGRAM of ICs • KIA6289N (IC14) BLOCK DIAGRAM - 2-21 -...
  • Page 29 - 2-22 -...
  • Page 30 • BA3126N (IC201) 2-channel head switch for radio cassette recorders - 2-23 -...
  • Page 31 • NJM2155 (IC401) BLOCK DIAGRAM & PIN CONFIGRATION • BU2090F (IC501) 12-bit, Serial IN, Parallel OUT driver Block diagram Control circuit DATA 12-bit shift register CLOCK Latch Output buffer (open drain) - 2-24 -...
  • Page 32 Pin No. Pin name Function BU2090/F/FS BU2092/F BU2092/FV DATA Serial data input CLOCK Data shift clock input Data latch clock input parallel data output parallel data output parallel data output parallel data output parallel data output parallel data output parallel data output N.C.
  • Page 33 Block diagram - 2-26 -...
  • Page 34 • KIA4558P/S (IC602) BIPOLAR LINEAR INTEGRATED CIRCUIT - 2-27 -...
  • Page 35 • STK-403-120 (IC700) - 2-28 -...
  • Page 36 • BA5810FP (IC803) - 2-29 -...
  • Page 37 • KA3082 (IC807) Bi-Directional DC Motor Driver Description The KA3082 is a monolithic integrated circuit designed for driving bi-directional DC motor with braking and speed control. - 2-30 -...

  • Page 38: Equivalent Circuit

    • KIA7805AP/API (IC940) THREE TERMINAL POSITIVE VOLTAGE REGULATORS 5V, 6V, 8V, 9V, 10V, 12, 15V, 18V, 24V. EQUIVALENT CIRCUIT - 2-31 -...
  • Page 39 - 2-32 -...
  • Page 40 ❏ BLOCK DIAGRAM STK403-120 IC700 LC72131M IC602 JK600 IC404-B IC404-A JK401 BU2090 +40V -40V TUNER/FUNTION/OP-AMP P-SENS SMPS Power code +12V +6.2V CD/MICOM/EXPENDER 2-33 2-34...

  • Page 41: Schematic Diagrams

    ❏ SCHEMATIC DIAGRAMS • MAIN SCHEMATIC DIAGRAM 2-35 2-36...
  • Page 42 • DECK SCHEMATIC DIAGRAM 2-37 2-38...
  • Page 43 • FRONT SCHEMATIC DIAGRAM 2-39 2-40...
  • Page 44 • SMPS-WIDE SCHEMATIC DIAGRAM 2-41 2-42...
  • Page 45 • CDP SCHEMATIC DIAGRAM 2-43 2-44...

  • Page 46: Wiring Diagram

    ❏ WIRING DIAGRAM 2-45 2-46...

  • Page 47: Printed Circuit Diagrams

    ❏ PRINTED CIRCUIT DIAGRAMS • MAIN P.C. BOARD (SOLDER SIDE) 2-47 2-48...
  • Page 48 • MAIN P.C. BOARD (COMPONENT SIDE) 2-49 2-50...
  • Page 49 • FRONT P.C. BOARD (SOLDER SIDE) 2-51 2-52...
  • Page 50 • FRONT P.C. BOARD (COMPONENT SIDE) 2-53 2-54...
  • Page 51 • SMPS P.C. BOARD 2-55 2-56...
  • Page 52 • CD MAIN P.C. BOARD (COMPONENT SIDE) • CD MAIN P.C. BOARD (SOLDER SIDE) 2-57 2-58...

  • Page 53: Section 3. Exploded Views

    SECTION 3. EXPLODED VIEWS ❏ CABINET AND MAIN FRAME SECTION...
  • Page 54 • TAPE DECK MECHANISM (A/R & A/S : LEFT A/S DECK)
  • Page 55 • TAPE DECK MECHANISM (A/R & A/S : RIGHT A/R DECK)
  • Page 56 • CD MECHANISM...
  • Page 57 MEMO MEMO 3-10...

  • Page 58: Section 4. Speaker Section

    SECTION 4. SPEAKER SECTION ❏ MODEL: LMS-M1040 LEFT RIGHT - 4-1 -...
  • Page 59 MEMO - 4-2 -...

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