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LG PF-43A20 Service Manual

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COLOR TV

SERVICE MANUAL

CHASSIS : MP-87B
MODEL : PF-43A20
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

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  Summary of Contents for LG PF-43A20

  • Page 1: Service Manual

    COLOR TV SERVICE MANUAL CHASSIS : MP-87B MODEL : PF-43A20 CAUTION BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
  • Page 2: Table Of Contents

    CONTENTS Contents ......................2 Safety Precautions ..................3 Servicing Precautions ..................4 Specifications ....................6 Control Descriptions ..................8 Alignment/Test Point Location Guide............11 Adjustment......................14 Troubleshooting .....................19 Component Location Guide .................26 Printed Circuit Board ..................27 Block Diagram ....................34 Wiring Diagram....................36 Exploded View ....................38 Exploded View Parts List................39 Replacement Parts List ................
  • Page 3: Safety Precautions

    SAFETY PRECAUTIONS IMPORT ANT SAFETY NOTICE Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by the Schematic Diagram and Replacement Parts List. It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent X-RADIATION, Shock, Fire, or other Hazards.
  • Page 4: Servicing Precautions

    SERVICING PRECAUTIONS CAUTION: Before servicing receivers covered by this service transistors and semicounductor "chip" components. The manual and its supplements and addenda, read and follow the following techniques should be used to help reduce the SAFETY PRECAUTIONS on page 3 of this publication. incidence of component damage caused by static by static NOTE: If unforeseen circumstances create conflict between the electricity.
  • Page 5 c. Qulckly move the soldering iron tip to the junction of the Fuse and Conventional Resistor component lead and the printed circuit foil, and hold it Removal/Replacement there only until the solder flows onto and around both the 1. Clip each fuse or resistor lead at top of the circuit board component lead and the foil.
  • Page 6: Specifications

    SPECIFICATIONS NOTE : Specifications and others are subject to change without notice for improvement. Video input system: Power requirements : ¡ ¡ Multi 26 System 100-270 Vac, 50/60HZ (Refer to Table 1) Intermediate Frequency Power consumption : ¡ ¡ Vision IF : 38.0MHz 210 Wmax.
  • Page 7 T able 1 : Receiving System (26 System) Receiving System Receiving Channel Function P P A A L L - - B B P P A A L L - - G G V V H H F F B B a a n n d d P P A A L L - - I I PAL/SECAM-B : : 2 2 - - 1 1 2 2...
  • Page 8: Control Descriptions

    9 or 4 PLAY sub pictures. P/STILL STOP 5. PSM (Picture Status Memory) recalls your preferred picture setting. 6. SSM (Sound Status Memory) recalls your preferred sound setting. 7. VCR BUTTONS (option) control a LG video cassette recorder. - 8 -...
  • Page 9 8. DUAL selects the language during dual language broadcast. selects mono sound during stereo broadcasts. POWER MUTE 9. TV/AV I/II selects TV or AV mode. 10. MENU selects a menu. TV/AV 11. ¡ª/¡ (Programme Up/Down) TEXT MENU switches the set on from standby. selects a programme or a menu item.
  • Page 10: Front Panel

    Front panel AV 2 TV/AV MENU VIDEO L/MONO S-VIDEO AUDIO 1. MAIN POWER (on the side of TV) 7. ¡ª /¡ (Programme Up/Down) switches the set on or off. switches the set on from standby. selects a programme or a menu item. 2.
  • Page 11: Alignment/Test Point Location Guide

    ALIGNMENT/TEST POINT LOCATION GUIDE SIGNAL Board (Component side) - 11 -...
  • Page 12 DEFLECTION Board (Component side) - 12 -...
  • Page 13 IF (Component side) PIP (Component side) CPT Board (Component side) VR902G VR902B VR902R - 13 -...
  • Page 14: Adjustment

    ADJUSTMENT INSTRUCTIONS ¡ Main VCO (Voltage Controlled Oscillator) § Safety Precautions Adjustment 1. It is safe to adjust after using insulating transformer between the power supply line and chassis input to prevent Test Point : the risk of electric shock and protect the instrument. 2.
  • Page 15 ¡ RF AGC (Auto Gain Control) Adjustment ¡ Cut-off Adjustment Test Point : J104/ J106 NOTE : This adjustment should be performed after warming up for 15 minutes at least. Adjust : VRI1 / VRP1 Test Point : Observing Display The RF AGC control (VRI1/ VRP1 ) was aligned at the time of Adjust : VR902R, 902G, 902B (Cut-off)
  • Page 16 RASTER SLANT/POSITION, FOCUS & CONVERGENCE ADJUSTMENT Caution : ¡ Lens and Electrical Focus Adjustment These adjustments have been factory aligned. Do not attempt 1. Preliminary steps to temper with these alignments. However, the effects of 1) The electrical focus, the raster slant and position must be adjacent receiver components, or replacement of picture tube provisional alignment.
  • Page 17: Convergence Adjustment

    4. Blue lens Adjustment 2) Horizontal Phase Adjustment. Press the volume ¢‚/¢” button and move the convex part 1) Turn the lens until the chromatic aberration changed to the middle of TV screen. purple to green which of 3.5 Cross-Hatch part from picture's center toward left.
  • Page 18: White Balance Adjustment

    6. Red Convergence Adjustment 1) Press TV/AV button and select the red cursor. 2) If necessary, cover B lens. 3) Adjust as same as the green convergence adjustment and coincide the red pattern with the green pattern. 7. Blue Convergence Adjustment 1) Press TV/AV button and select the blue cursor.
  • Page 19: Troubleshooting

    TROUBLESHOOTING NO PICTURE/ NO COLOR Is the CVBS signal at pin 4 of P101A normal? Check IF Board Is the CVBS signal at Pin 40 of IC201 normal? Check/Replace IC201 Is the Y signal at Pin 3 of IC1D normal? Check/Replace IC1D, Q202 Is the Y signal at Pin 37...
  • Page 20 NO PIP In case of PIP (AV) In case of PIP (RF) Is there video signal at Is there CVBS signal at pin 29 of IC201? pin 24 of ICP3? Check/Replace IC201 Check Check I C Bus TUNER/IF parts Is there video signal at of PIP pin 26 of ICP3 Check PP2,...
  • Page 21 NO TELETEXT Check the voltage of CT75(+) Abnormal Normal Abnormal Check the 12V line Check the voltage of CT76(+) to be correct Check/Replace ICT75, PT75 4.8~ 5.2V Check if the video signal inputs at pin 8 of ICT74. Check if the video signal inputs at the pin 40 of IC201.
  • Page 22 NO PICTURE/NO SOUND (RASTER OK) Does the Auto search operate normal? Is the CVBS signal at Check the voltage Pin 4 of P101A normal? of Tuner (33V, 5V) Check/Replace Check IF Board ZD101, ZD102, R106, R108 GO TO Check pins 20,21, NO PICTURE Block 22,39 of IC1 NO SOUND Block...
  • Page 23 NO SOUND (PICTURE OK) Check Sound system of station MENU OSD (Manual Programme) BG/I/DK Is the voltage at pin 25 Is the voltage at Pin 25 of IC1 0V(Low)? of IC1 5V(High)? Is the SIF signal at Pin 24 of ICI1 normal? Check/Replace ICI1 Are the Audio signal at Pin...
  • Page 24 NO RASTER Check +B voltage at R406. Normal Open Is the voltage at Check F801A Pin 3 of IC501 9V? Check 5V, 9V, Check/Replace 12V lines F801A, D821, IC825 Does the square Check the voltage waveform from pin 4 of of C809(+) IC501 appear? Check/Replace...
  • Page 25 INCORRECT CONVERGENCE Does the static convergence correct? Incorrect Dynamic Incorrect Static Check the input voltage at Readjust static convergence P82PD. by remote controller Normal Abnormal Not controlled Controlled Check pulse pin 125 Check voltage on the Are there pulse signal of IC2051 (4MHz) SMPS PCB at pin 121 of IC2051...
  • Page 26: Component Location Guide

    COMPONENT LOCATION GUIDE(SIGNAL) AC1 ..F1 C471..F5 C621..B4 D604 ..C4 P303A..F1 R23 ..G1 R102..B1 R516 ..D5 R658..B4 R24..F1 R103..B1 R517 ..D5 R659..A5 AR1..G1 C472..F5 C622 ..C4 D605..A4 P401A ..G5 AR2 ..F1 C473..F5 C623..B4 D606 ..C4 P402A..F5 R25..F2 R104 ..C1 R518 ..D5 R666 ..C4 R105 ..C1 R519 ..G4...
  • Page 27: Printed Circuit Board

    - 27 -...
  • Page 28 - 28 -...
  • Page 29 - 29 -...
  • Page 30 - 30 -...
  • Page 31 COMPONENT LOCATION GUIDE(DEF) C301..B2 C432 ..C1 D410..B3 G43 ..C1 Q308 ..E4 R344..E2 R440..A1 R2032..B4 R345..E3 R441..A2 R2033..E5 C302..B2 C433..B2 D412..A2 G44 ..C1 Q309 ..E4 C303..B3 C434..A2 D413..A1 G45 ..B1 Q310 ..A4 R346..E3 R442..A2 R2034 ..C5 R443 ..D3 R2047..E4 C304..A3 C435..A2 D414..A1 G46 ..A1 Q311 ..A4...
  • Page 32 IF/MPX - 32 -...
  • Page 33 AV/DCF A/V 2 - 33 -...
  • Page 34: Block Diagram

    BLOCK DIAGRAM - 34 -...
  • Page 35 BLOCK DIAGRAM(SIGNAL) - 35 -...
  • Page 36: Wiring Diagram

    WIRING DIAGRAM POWER S/W PWB P803 P802 AV3 PWB P201PSA CONTROL PWB P202PSC DIGI-CON PCB P02A HV BLOCK P110PD P43PD P82PD FOCUS PACK "C" "A" "B" P301A GND1B GND1G "B" CRT PCB "G" CRT PCB "R" CRT PCB GND2G GND1R GND2B P45PD P911R...
  • Page 37 MEMO - 37 -...
  • Page 38: Exploded View

    EXPLODED VIEW - 38 -...
  • Page 39: Exploded View Parts List

    SCREEN,SGS7243N 3720V00007B PANEL,RIGHT 6871VSM258A PCB ASSY,A/V3 6871VSM257A PCB ASSY,CONTROL 3720V00011E PANEL ASSY,CONTROL 3580V00007B DOOR,CONTROL 5020V00074B BUTTON,CONTROL 8KEY ABS 5020V00247A BUTTON,POWER PF-43A20 ABS . 320-070R SPRING,COIL 3091V00025C CABINET ASSY,WOOD 4980V00039A SUPPORTER,CONV.PCB 3550V00011D COVER ASSY,BOTTOM 3530V00027B GRILLE ASSY,SPEAKER 3300V00009A PLATE,CRT COVER 4980V00023A...
  • Page 40: Replacement Parts List

    0DD184009AA DIODE,SWITCHING KDS184S 85V 300MA D2057 IC2051 0IGS961200A IC,MDC9612 144QFP BK DIGITAL CONV D2201 0DD181009AB DIODE,SWITCHING KDS181 85V 300MA 0IZZVD0005F IC,PF-43A20 D-CON MICOM ASSY 44PI IC2052 D2202 0DD181009AB DIODE,SWITCHING KDS181 85V 300MA 0IKE744200A IC,KIA7442P TO-92 NEGA.RESET(4.2V IC2053 0DD414809ED DIODE,DS4148 IC2054...
  • Page 41 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION D501 0DD414809ED DIODE,DS4148 ZD2004 0DZ120009AA DIODE,ZENER Z12BM TA DIODE,DS4148 DIODE,ZENER DTZ5.1BTT11(CHIP) D502 0DD414809ED ZD2051 0DZ511109AA 0DD414809ED DIODE,DS4148 0DZ120009AA DIODE,ZENER Z12BM TA D503 ZD301 D504 0DD414809ED...
  • Page 42 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION Q205 0TR319809AA TR,KTC3198-TP-Y (KTC1815)KEC Q2351 0TR387500AA TR,CHIP 2SC3875S(ALY) KEC TR,CHIP 2SA1504S(ASY) KEC TR,CHIP 2SC3875S(ALY) KEC Q206 0TR150400BA Q2352 0TR387500AA 0TR387500AA TR,CHIP 2SC3875S(ALY) KEC 0TR387500AA TR,CHIP 2SC3875S(ALY) KEC Q207...
  • Page 43 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION Q902R 0TR319809AA TR,KTC3198-TP-Y (KTC1815)KEC CP82 0CE107DF618 C,ELECTROLYTIC 100UF STD 16V M TR,KTC3229 (KTC2068),KEC C,ELECTROLYTIC 470UF STD 16V M Q904B 0TR322900AA CP83 0CE477DF618 0TR322900AA TR,KTC3229 (KTC2068),KEC 0CE108DF618...
  • Page 44 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION 0CN1030F679 C,TUBULA(HIGH DIELE) 0.01MF 16V M C2034 0CN1510K519 C,TUBULA(HIGH DIELE) 150P 50V K C,TUBULA(HIGH DIELE) 0.01MF 16V M C,TUBULA(HIGH DIELE) 150P 50V K C101 0CN1030F679 C2035...
  • Page 45 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION C26D 0CE476DF618 C,ELECTROLYTIC 47UF STD 16V M C422 0CK22101515 C,CERAMIC(HIGH DIELE) 220P 1KV K B TP5 C,ELECTROLYTIC 4.7UF STD 50V M C,ELECTROLYTIC 2200UF STD 16V M C261 0CE475DK618...
  • Page 46 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION C520 0CE106DK618 C,ELECTROLYTIC 10UF STD 50V M C814 181-014Z C,MPP 1.6KV 0.0033UF J C,ELECTROLYTIC 3.3UF STD 50V M C,CERAMIC(HIGH DIELE) 470PF 500V K C521 0CE335DK618 C824...
  • Page 47 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION C904B 181-033T CAPACITOR 2KV B 222K TP7.5 LP17 0LA0102K119 INDUCTOR,10UH K INDUCTOR,10UH K C904G 181-033T CAPACITOR 2KV B 222K TP7.5 LP18 0LA0102K119 181-033T CAPACITOR 2KV B 222K TP7.5...
  • Page 48 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION L406 150-L01S COIL,H-LINEARITY 40UH P917G 387-A26J CONNECTOR ASSY,6P MIS 2.5MM (L=300) COIL,CHOKE WIDTH 3600UH CONNECTOR ASSY,4P MIS 2.5MM (L=300) L407 150-W01D P919B 387-A24J 0LA0102K119 INDUCTOR,10UH K...
  • Page 49 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION RT89 0RD4700F609 R,CARBON FILM 1/6W 5 R2020 0RS2200J607 R,METAL FILM OXIDE 220 1W 5% R,CARBON FILM 1/6W 5 R,METAL FILM OXIDE 5.60 2W 5% RT90 0RD4700F609 R2021...
  • Page 50 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION R274 0RD2200F609 R,CARBON FILM 1/6W 5 R351 0RD4701F609 R,CARBON FILM 4.7K 1/6W 5 R,CARBON FILM 1.0K 1/6W 5 R,CARBON FILM 1.0K 1/6W 5 R275 0RD1001F609 R352...
  • Page 51 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION R434 0RS0152J607 R,METAL FILM OXIDE 15 1W 5% TA62 R510 0RD1001F609 R,CARBON FILM 1.0K 1/6W 5 R,METAL FILM OXIDE 470 2W 5% R,CARBON FILM 1.0K 1/6W 5 R435...
  • Page 52 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION R641 0RD1001F609 R,CARBON FILM 1.0K 1/6W 5 R841 0RS0102K607 R,METAL FILM OXIDE 10 2W 5% R,CARBON FILM 1.0K 1/6W 5 R,CARBON FILM 1/6W 5 R642 0RD1001F609...
  • Page 53 166-F01G SG901R 165-004A SPARK GAP,AG20PT 152F-L3N/S-23 ACCESSORIES SG902B 165-004A SPARK GAP,AG20PT 152F-L3N/S-23 SG902G 165-004A SPARK GAP,AG20PT 152F-L3N/S-23 3828VA0160F MANUAL,OWNERS MP87B.LG EN 7WTX 341C . SPARK GAP,AG20PT 152F-L3N/S-23 SG902R 165-004A 6710V00007W REMOTE CONTROLLER MISCELLANEOUS SWITCH SW01 140-191A SWITCH,TACT,KHH-15910 172-050Y CABLE ASSY,COAXIAL(L=70MM)
  • Page 54 The components identified by mark critical for safety. LOCA. NO PART NO DESCRIPTION TU151 113-243B TUNER,TUGG9-A07P(HYPER) T401 6174Z-6079D F.B.T,FTMPC11-T6079D VA801 164-003D VARISTOR,SVC 561D-14A - 54 -...
  • Page 55 VIDEO AUDIO...
  • Page 59 Oct., 1998 P/NO : 3828VD0053C Printed in Korea...