LG PF-52A70 Service Manual
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LG PF-52A70 Service Manual

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COLOR TV
SERVICE MANUAL
CHASSIS : MP-87B
MODEL : PF-52A70
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
website:http://biz.LGservice.com
e-mail:http://www.LGEservice.com/techsup.html

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Summary of Contents for LG PF-52A70

  • Page 1 COLOR TV SERVICE MANUAL CHASSIS : MP-87B MODEL : PF-52A70 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 ....................35 Wiring Diagram....................37 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 160-270 Vac, 50/60HZ (Refer to Table 1) Power consumption : Intermediate Frequency ¡ ¡ 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 TV/AV SSM PSM MENU STAND BY (L/MONO) AUDIO VIDEO S-VIDEO MAIN POWER <SIDE OF TV> 1. MAIN POWER (side of TV) switches the set on or off. 2. AUDIO/VIDEO(or S-VIDEO) IN SOCKETS (AV 2) Connect the audio/video (or S-video) out sockets of external equipment to these sockets.

  • 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) VR902B VR902R VR902G - 13 -...

  • Page 14: Adjustment

    ADJUSTMENT INSTRUCTIONS § Safety Precautions ¡ Main VCO (Voltage Controlled Oscillator) 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 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 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 (RF) In case of PIP (AV) 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 Readjust static convergence Check the input voltage at P82PD. by remote controller Abnormal Controlled Normal Not 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) R658..B4 AC1 ..F1 C471..F5 C621..B4 D604 ..C4 P303A..F1 R23 ..G1 R102..B1 R516 ..D5 D605..A4 P401A ..G5 R24..F1 R103..B1 R517 ..D5 R659..A5 AR1..G1 C472..F5 C622 ..C4 AR2 ..F1 C473..F5 C623..B4 D606 ..C4 P402A..F5 R25..F2 R104 ..C1 R518 ..D5 R666 ..C4 R26 ..G2 R105 ..C1...

  • Page 27: Printed Circuit Board

    PRINTED CIRCUIT BOARD SIGNAL - 27 -...
  • Page 28 POWER - 28 -...
  • Page 29 CONVERGENCE(TOP) CONVERGENCE(BOTTOM) - 29 -...
  • Page 30 DEFLECTION - 30 -...
  • Page 31 COMPONENT LOCATION GUIDE(DEF) C301..B2 C432 ..C1 D410..B3 G43 ..C1 Q308 ..E4 R344..E2 R440..A1 R2032..B4 G44 ..C1 Q309 ..E4 R345..E3 R441..A2 R2033..E5 C302..B2 C433..B2 D412..A2 C303..B3 C434..A2 D413..A1 G45 ..B1 Q310 ..A4 R346..E3 R442..A2 R2034 ..C5 R347..E3 R443 ..D3 R2047..E4 C304..A3 C435..A2 D414..A1 G46 ..A1...
  • Page 32 IF/MPX - 32 -...
  • Page 33 AV/DCF A/V 2 - 33 -...
  • Page 34 CONTROL - 34 -...

  • Page 35: Block Diagram

    BLOCK DIAGRAM - 35 -...
  • Page 36 BLOCK DIAGRAM(SIGNAL) - 36 -...

  • Page 37: Wiring Diagram

    WIRING DIAGRAM CONTROL PWB POWER S/W. P01PSC AV3 PWB P201PSA P03PSP PRE-AMP PWB HV BLOCK P85PS P50PSG P50PSB P917G P917B P50PSR "G" CRT PCB "B" CRT PCB "R" CRT PCB P911G P919G P919B P911R P45PD GND2B P81PS GND1R GND2G GND1G GND1B P801A "...

  • Page 38: Exploded View

    EXPLODED VIEW - 38 -...

  • Page 39: Exploded View Parts List

    EXPLODED VIEW PARTS LIST The components identified by mark critical for safety. Replace only with part number specified. Part No. Description 3680V00004A LENS,USPL DELTA 67D 4810V00111M BRACKET,BLUE COUPLER+CPTASSY 4810V00111L BRACKET,GREEN COUPLER+CPTASSY 4810V00111K BRACKET,RED COUPLER+CPTASSY 120-C78H SPEAKER,WOOFER 8OHM 25W/35W 6400VG0001B SPEAKER,TWEETER 8OHM 20W/30W 6150V-1007B DY,DAV4851(1H) 07”...

  • Page 40: Replacement Parts List

    The components identified by mark critical for safety. REPLACEMENT PARTS LIST Replace only with part number specified. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION IC2053 0IKE744200A IC,KIA7442P TO-92 NEGA.RESET(4.2V IC2054 0IZZVD0005H IC PF-60A30 D-CON EEPROM ASSY 8PI ICP1 0ISA755500A IC,LA7555 24SD PLL VIF+SIF...
  • Page 41 LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION D808 0DD060009AC DIODE,TVR06J 0.6A/600V 250NS ZD502 0DZ510009AB DIODE,ZENER MTZ5.1B,TP(52MM) DIODE,TVR06J 0.6A/600V 250NS DIODE,ZENER MTZJ7.5B DO34 0.5W D810 0DD060009AC ZD801 0DZ750009AG D821 0DD560000AA DIODE,RECTIFIER D5SB60 BRIDGE(5A/600V) ZD802 0DZ120009AF DIODE,ZENER MTZJ12B DO34 500MW D841 0DD420000BB DIODE,D4L20U SHINDENGEN...
  • Page 42 LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION Q403 0TR319809AA TR,KTC3198-TP-Y (KTC1815)KEC Q2166 0TF211009AE FET,KTK211S-Y TP SOT-23 KEC TR,KTA1274-Y TO-92L TP KEC TR,CHIP 2SC3875S(ALY) KEC Q405 0TR127409AB Q2167 0TR387500AA Q406 0TR205900AA TR,KTD2059-O,TO-220IS,100V,5A,KEC Q2168 0TR387500AA TR,CHIP 2SC3875S(ALY) KEC Q412 0TR322709AA TR,KTC3227-Y,TP(KTC1627A),KEC Q2201...
  • Page 43 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film in the P/No. means as follows; CE : Electrolytic RN : Metal Film RF : Fusible LOCA.
  • Page 44 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film in the P/No. means as follows; CE : Electrolytic RN : Metal Film RF : Fusible LOCA.
  • Page 45 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film The components identified by mark charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film critical for safety. in the P/No. means as follows; CE : Electrolytic RN : Metal Film Replace only with part number specified.
  • Page 46 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film in the P/No. means as follows; CE : Electrolytic RN : Metal Film RF : Fusible LOCA.
  • Page 47 The components identified by mark critical for safety. Replace only with part number specified. LOCA. NO PART NO DESCRIPTION LOCA. NO PART NO DESCRIPTION 0LA0102K119 INDUCTOR,10UH K FERRITE CORE INDUCTOR,10UH K L101 0LA0102K119 FB801 125-022K CORE (CIRC),FERRITE 1UH TAPING L151 0LA0102K119 INDUCTOR,10UH K FB802...
  • Page 48 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film The components identified by mark charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film critical for safety. in the P/No. means as follows; CE : Electrolytic RN : Metal Film Replace only with part number specified.
  • Page 49 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film in the P/No. means as follows; CE : Electrolytic RN : Metal Film RF : Fusible LOCA.
  • Page 50 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film in the P/No. means as follows; CE : Electrolytic RN : Metal Film RF : Fusible LOCA.
  • Page 51 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film The components identified by mark charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film critical for safety. in the P/No. means as follows; CE : Electrolytic RN : Metal Film Replace only with part number specified.
  • Page 52 For Capacitor & Resistors, the CC, CX, CK, CN : Ceramic RD : Carbon Film charactors at 2nd and 3rd digit CQ : Polyestor RS : Metal Oxide Film in the P/No. means as follows; CE : Electrolytic RN : Metal Film RF : Fusible LOCA.
  • Page 53 SPARK GAP,AG20PT 152F-L3N/S-23 SG902B 165-004A 166-C02C FILTER(CIRC),TRAP TPS5.5MB-TF21 5.5MHZ SG902G 165-004A SPARK GAP,AG20PT 152F-L3N/S-23 ACCESSORIES SG902R 165-004A SPARK GAP,AG20PT 152F-L3N/S-23 3828VA0139C MANUAL,OWNERS.LG AR/EN SWITCH 6710V00007W REMOTE CONTROLLER SW01C 6600VR1001A SWITCH,TACT SKHH 10908 12V/50MAV MISCELLANEOUS SW02C 6600VR1001A SWITCH,TACT SKHH 10908 12V/50MAV SW03C 6600VR1001A...
  • Page 54 VIDEO AUDIO...
  • Page 58 Apr., 2000 P/NO : 3828VD0053J Printed in Korea...

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