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LG CF-21Q20EH Service Manual

Chassis mc-014a
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COLOR TV
SERVICE MANUAL
CHASSIS : MC-014A
MODEL:RF-21FA20/Q/PQ
MODEL:CF-21Q20EH
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 CF-21Q20EH

  • Page 1 COLOR TV SERVICE MANUAL CHASSIS : MC-014A MODEL:RF-21FA20/Q/PQ MODEL:CF-21Q20EH CAUTION BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
  • Page 2: Table Of Contents

    CONTENTS Contents ......................... 2 Safety Precautions ....................3 Specifications ..................... 4 Control Descriptions ..................5 Disassembly Instructions ................8 Adjustment Instructions ................9 T rouble Shooting ....................12 Exploded View .................... 16,18 Exploded View Parts List ................17,19 Replacement Parts List ................20 SVC.
  • 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: Specifications

    SPECIFICATIONS Note : Specification and others are subject to change without notice for improvement. Video input system: SOUND IF : 33.4MHz (B/G) PAL-B/G, D/K, I/I 32.9MHz (I/I) SECAM-B/G, D/K 32.4MHz (D/K) NTSC 4.43(AV) Power requirement : 110~240V, 50/60Hz Intermediate Frequency (Unit : MHz) VISION IF : 38.9MHz Power consumption : 95W COLOR IF : 34.47MHz(4.43)
  • Page 5: Control Descriptions

    PLAY STOP P/STILL 9. PSM (Picture Status Memory) recalls your preferred picture setting. 10. SSM (Sound Status Memory) recalls your preferred sound setting. 11. VCR BUTTONS (option) control a LG video cassette recorder. (With / Without PIP) - 5 -...
  • Page 6 12. I/II selects the language during dual language broadcast (option). selects the sound output. 13. LIST displays the programme table. 14. PIP BUTTONS (option) PIP/ switches the sub picture on or off. PR +/- selects a programme for the sub picture. POWER SWAP PICTURE...
  • Page 7 Front panel CT-21Q21 series TV/AV VIDEO L/MONO AUDIO POWER AV 2 5 6 8 RF-21FA20 series MENU ON/Off 1. MAIN POWER switches the set on or off. 2. POWER/STANDBY INDICATOR illuminates brightly when the set is in standby mode. dims when the set is switched on. 3.
  • Page 8: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS Important note Chassis Assy Removal This set is disconnected from the power supply through the Grasp both side of Frame and pull it backward smoothly. converter transformer. An isolating transformer is necessary for service operations on the primary side of the converter transformer.
  • Page 9: Adjustment Instructions

    ADJUSTMENT INSTRUCTIONS Safety Precautions 1. It is safe to adjust after using insulating transformer between the power supply line and chassis input to prevent the risk of electric shock and protect the instrument. 2. Never disconnect leads while the TV receiver is on. 3.
  • Page 10 6) Adjust High Light status of RG and BG with VOL+ or VOL- at CG:370 until X=268!8,Y=273!8. 7) Repeat above step 5) and 6) until each status of High Light and Low Light. LOW LIGHT HIGH LIGHT 43 ! 1 FL 4.5 ! 1 FL LG 21” FLAT - 10 -...
  • Page 11 OPTION Adjustment 1.OPTION 1 Function 3.OPTION 3 Function Remark Option Code Function Option Code Function Remark NO 200PR Option Rear AV2 Option NO YUV/W 200PR YUV/W With 200PR Option YUV/S-WOOFER China+Australia Option CC GAME Except China & Australia CH+AU GAME China &...
  • Page 12: T Rouble Shooting

    T rouble Shooting No Power ON(SMPS working) Check pin31 of IC01 High Low(=0V) Check the voltage at Check & Replace pin 54 of IC01. Q05, IC851, IC802(3), IC856 3.3V Check & Replace Check & Replace Check the H-Out voltage IC853(3), FR406, IC01,FR403,R413, at pin24 of IC01 D408,D858,Q856...
  • Page 13 Check the heater element Check the Heater voltage 6.0~6.4Vrms Check & Replace Increase the screen FR401 Voltage of FBT Normal Check & Replace Retrace line Screen is Black is visible Check the waveform Check FBT & CPT at pin21 of IC01 socket &...
  • Page 14 No Sound(Picture OK) Check the voltage at pin10 of IC601(Sound Amp) Check & Replace Check the waveform F851,FB853,D850 at pin24,25 of ICN01 Check the voltage Check the waveform at pin8 of IC601 at pin47 of ICN01 Check & Replace Check & Replace IC601,QN01-02,P605(6)A Q601,IC01 NORMAL...
  • Page 15 Don t Catch Channel Check the voltage at pin9 of Tuner(33V) Check & Replace Check the voltage at F854,D861,R103,ZD101 pin7 of Tuner(5V) Check the waveform at Check & Replace pin14 of IC141(CVBS) L102,Tuner Check & Replace Check the waveform at Z101,IC141 pin21 of IC01(CVBS In) Check &...
  • Page 16: Exploded View

    EXPLODED VIEW:21FA20 P801 - 16 -...
  • Page 17: Exploded View Parts List

    The components identified by mark critical for safety. EXPLODED VIEW PARTS LIST Replace only with part number specified. LOCA. NO PART NO DESCRIPTIONS 343-B52A SUPPORTER,PCB 2426GDB30AI CPT SET,A51QDJ279X 17K7NI 2426GDB30AZ CPT SET,A51QDJ279X 00M7NI 120-C77G SPEAKER,GENERAL C122P02K1459 8 OHM 1 6401VA0011B SPEAKER ASSY,WOOFER 150-D02X COIL,DEGAUSSING CU 21”...
  • Page 18 EXPLODED VIEW:21Q20 P801 - 18 -...
  • Page 19 The components identified by mark critical for safety. EXPLODED VIEW PARTS LIST Replace only with part number specified. LOCA. NO PART NO DESCRIPTIONS 2426GDB3804 CPT SET,A51QDJ279X 17K7NI 120-D38C SPEAKER,8 OHM 15/25W 6401VA0011B SPEAKER ASSY,WOOFER 120-D18C SPEAKER,WOOFER C100R54K1452 8 OHM 20/3 150-D02X COIL,DEGAUSSING CU 21”...
  • Page 20: 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 D858 0DD200009AH DIODE,RECTIFIER RU2AMV(1) TP D861 0DD060009AC DIODE,TVR06J 0.6A/600V 250NS HIC01 0IZZVF0017B IC,GAME MODULE D862 0DD110009DB DIODE,RECTIFIER RM11CV(1) TP...
  • Page 21 For Capacitor & Resistors, CC, CX, CK, CN : Ceramic RD : Carbon Film The components identified by mark the charactors at 2nd and 3rd CQ : Polyestor RS : Metal Oxide Film critical for safety. digit in the P/No. means as CE : Electrolytic RN : Metal Film Replace only with part number specified.
  • Page 22 For Capacitor & Resistors, CC, CX, CK, CN : Ceramic RD : Carbon Film The components identified by mark the charactors at 2nd and 3rd CQ : Polyestor RS : Metal Oxide Film critical for safety. digit in the P/No. means as CE : Electrolytic RN : Metal Film Replace only with part number specified.
  • Page 23 For Capacitor & Resistors, CC, CX, CK, CN : Ceramic RD : Carbon Film The components identified by mark the charactors at 2nd and 3rd CQ : Polyestor RS : Metal Oxide Film critical for safety. digit in the P/No. means as CE : Electrolytic RN : Metal Film Replace only with part number specified.
  • Page 24 The components identified by mark For Capacitor & Resistors, CC, CX, CK, CN : Ceramic RD : Carbon Film the charactors at 2nd and 3rd CQ : Polyestor RS : Metal Oxide Film critical for safety. digit in the P/No. means as CE : Electrolytic RN : Metal Film Replace only with part number specified.
  • Page 25 For Capacitor & Resistors, CC, CX, CK, CN : Ceramic RD : Carbon Film The components identified by mark the charactors at 2nd and 3rd CQ : Polyestor RS : Metal Oxide Film critical for safety. digit in the P/No. means as CE : Electrolytic RN : Metal Film Replace only with part number specified.
  • Page 26 0RD2403F609 240K OHM 1/6 W 5.00% TA52 R1650 0RD0331F609 3.3 OHM 1/6 W 5.00% TA52 SW01 140-315A SWITCH,TACT SKHV17910B LG C&D NON 12V R1651 0RD0331F609 3.3 OHM 1/6 W 5.00% TA52 SW02 140-315A SWITCH,TACT SKHV17910B LG C&D NON 12V R1652 0RD1000F609 100 OHM 1/6 W 5.00% TA52...
  • Page 27 P/N : 3854VA0087A-S1(1/2) Date : 2001.03.19...
  • Page 28 PRINTED CIRCUIT BOARD P/N: 3854VA0087A-S1(2/2) COMPONENT LOCATION GUIDE DATE: 2001.03.19 C01 ..B2 C501 ..C3 D408 ..E5 J18 ...B2 J105 ..D1 JP44..D5 Q01 ..D1 R201 ..D5 R542 ..C2 TP12 ..B4 C02 ..B2 C503 ..B3 D410 ..G3 J19 ...B1 J106 ..D4 JP45..D5 Q02 ..E1 R202 ..E5 R543 ..C2...
  • Page 29: Svc. Sheet

    SVC. SHEET:3854V A0087A-S1...
  • Page 30 Mar.,2001 P/NO : 3828VD0070E...

This manual is also suitable for:

Rf-21fa20Rf-21fa20qRf-21fa20pq