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LG CF-20/21S42EH Service Manual

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P/NO : 3828VD0062G
Jan, 2001
Printed in Korea
COLOR TV

SERVICE MANUAL

CHASSIS : MC-84D
MODEL : CF-20/21S42EH
MODEL :
CF-20/21S12EH
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
DTS
PR
SOUND PICTURE
POWER
MENU
VOL
VOL
OK
PR
website:http://biz.LGservice.com
e-mail:http://www.LGEservice.com/techsup.html

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  Summary of Contents for LG CF-20/21S42EH

  • Page 1: Service Manual

    COLOR TV SERVICE MANUAL CHASSIS : MC-84D MODEL : CF-20/21S42EH MODEL : CF-20/21S12EH CAUTION BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. Jan, 2001 SOUND PICTURE P/NO : 3828VD0062G Printed in Korea POWER MENU...
  • Page 2: Table Of Contents

    CONTENTS Contents ........................ 2 Safety Precautions ....................3 Specifications ..................... 4 Control Descriptions ..................6 Disassembly Instructions ................9 Adjustment ......................10 T roubleshooting....................14 Exploded View ....................16 Exploded View Parts List ................17 Replacement Parts List ................20 SVC. Sheet ........................ - 2 -...
  • 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

    SPECIFICA TIONS Note:Specifications and others are subject to change without notice for improvement. Power requirement: External in/output: Headphone, SCART or Phone Jack : Option ¡ ¡ AC 110-240V, 50/60Hz (Cold SMPS) Audio-In ; 0.4Vrms¡ 3dB, over 10Kohm Audio-Out ; 0.4Vrms¡ 3dB, below 1Kohm Tuning system: ¡...
  • Page 5 T able 1 : Receiving System (26 System) Receiving System Receiving Channel Function PAL-B PAL-G VHF Band PAL-I, I/I PAL/SECAM-B : 2-12 PAL/SECAM-D : 1-12 PAL-D SECAM-K1 : 2-9 NTSC-M (US) : 2-13 PAL-K NTSC-M (JAPAN) : 1-12 Reception of broadcast and play-back for Video Tape Recorder SECAM-B UHF Band...
  • Page 6: Control Descriptions

    DESCRIPTION OF CONTROLS All the functions can be controlled with the remote control handset. Some functions can also be adjusted with the buttons on the front panel of the set. Remote control handset Before you use the remote control handset, please install the bat- teries.
  • Page 7: Battery Installation

    11. SSM (Sound Status Memory) (option) recalls your preferred sound setting. 12. TV/AV selects TV or AV mode. clears the menu from the screen. 13. DTS (Digital Turbo System) SOUND (option) selects Digital sound. DTS PICTURE (option) selects Digital picture. Note : : No function.
  • Page 8: Front Panel

    Front panel SOUND PICTURE POWER MENU Side panel 1. MAIN POWER ( POWER) switches the set on or off. 2. POWER/STANDBY INDICATOR ( r r ) illuminates brightly when the set is in standby mode. dims when the set is switched on. 3.
  • Page 9: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS Chassis Assy Removal Important note Grasp both side of Frame and pull it backward smoothly. This set is disconnected from the power supply through the converter transformer. An isolating transformer is necessary for service operations on the primary side of the converter transformer.
  • Page 10: Adjustment

    ADJUSTMENT Safety Precautions 1. It is safe to adjust after using insulating transformer TUNER 6700VPF009D 6700VPF003B between the power supply line and chassis input to prevent the risk of electric shock and protect the 2.6 ! 0.5V 2.7 ! 0.5V AGC Voltage instrument.
  • Page 11 3. Deflection Initial Setup Data level because loud TV sound can disturb other lodger's private business. Status Default 21" LG 20" LG The HOTEL manager select maximum volume level proper for HOTEL. 3. Only Audio without Video source available through A/V...
  • Page 12 OPTION Adjustment (SVC MODE:OPTION-1, OPTION-2) NOTE: When the EEPROM has been replaced, the Option data should be restored as the function of individual system OPTION Data SYSTEM SCART and specification. 1) Press OK buttons on both TV set and Remote Controller at the same time to get into SVC mode.
  • Page 13 Table 3. OPTION 2 Function OPTION Data CHINA LANG. HOTEL GAME BOOSTER Option Code Function Remark Normal Condition Fast Filter IF-PLL FFI Active (for excessive RF signal) W/O Chinese NICAM Chinese Model only CHINA Chinese NICAM Multi Language (M=0) Language varies by LANG.
  • Page 14: Troubleshooting

    TROUBLESHOOTING NO RASTER CHECK +B at D807 cathode Normal Abnormal Open Check Is the voltage at pin37 FUSE of AC line & 12 of IC501 8V? Check /replace Check the in/out Fuse,DB801,IC801 of IC841 Check the voltage Check pin40 of C806 of IC501(H-out) Check &replace 254~340V...
  • Page 15 NO SOUND / PICTURE OK Select correct system in MENU Check the waveform of Q651 collector Check / replace Q651 Check the voltage Check the waveform of IC101(logic) of pin3 of IC202 Check / replace Check demodulated Q653,654 signal of pin15 Check demodulated of input pin of IC601 or 602 Check the Vcc...
  • Page 16: Exploded View

    EXPLODED VIEW:20/21S42EH 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. PART NO DESCRIPTIONS 21" 20" 2426GCA40CD 2426GDA60CB CPT SET 120-D38C 120-D38C SPEAKER,8 OHM 15/25W 87 4810V00190B 4810V00190B BRACKET,SPK(LGEIL LOCAL) 3550V00085B 3550V00085B COVER,SPK(LGEIL LOCAL) 150-D02Y 150-D02X COIL,DEGAUSSING...
  • Page 18 EXPLODED VIEW:20/21S12EH P801 - 18 -...
  • Page 19 The components identified by mark critical for safety. EXPLODED VIEW PARTS LIST Replace only with part number specified. PART NO DESCRIPTIONS 21" 20" 343-B52A 343-B52A SUPPORTER,PCB 2426GCA40CD 2426GCA60CB CPT SET 120-D38F 120-D38F SPEAKER,C131P01-044K14 8 OHM 4810V00071B 4810V00071B BRACKET,COVER (SPK) 150-D02Y 150-D02X COIL,DEGAUSSING 170-A01D...
  • Page 20: Replacement Parts List

    REPLACEMENT PARTS LIST 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 follows;...
  • Page 21 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 22 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 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 SPARK GAP,SSA-351N-A1 350V 30% 5MM SG903 SG904 6918VAX002A SPARK GAP,SSA-351N-A1 350V 30% 5MM SWITCH 140-315A SW001 SWITCH,TACT SKHV17910B LG C&D NON 12V SW002 140-315A SWITCH,TACT SKHV17910B LG C&D NON 12V SW003 140-315A SWITCH,TACT SKHV17910B LG C&D NON 12V SW004 140-315A SWITCH,TACT SKHV17910B LG C&D NON 12V...
  • Page 26 Service Sheet of MC-84A Service Sheet of MC-84A P/N : 3854VA0037A-S Video (Composite) (980427) Sound WAVEFORM Chroma...
  • Page 27 PRINTED CIRCUIT BOARD BLOCK DIAGRAM MAIN AV STEREO EAR PHONE SPEAKER REAL STEREO (FRONT) OPTION PART & NICAM FILTER DA4445B C LINE MSP3410D SOUND AMP. TDH7297 (MONO) LOCAL KEY PRE AMP AV STEREO TDA7429S PROM MICOM RGB AMP. TDA6107Q KIA4558 Turbo Key VER.
  • Page 28: Svc. Sheet

    SVC. SHEET : 3854V A0079A-S...

This manual is also suitable for:

Cf-20/21s12ehCf-21s42ehCf-20s42ehCf-20s12ehCf-21s12eh