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LG 20LS7DC Service Manual
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LG 20LS7DC Service Manual

Lg lcd tv service manual
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See also: Owner's Manual , Setup Manual
LCD TV

SERVICE MANUAL

CHASSIS : LA74E
MODEL : 20LS7D(C)
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
website:http://biz.LGservice.com
20LS7D(C)-UB

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Summary of Contents for LG 20LS7DC

  • Page 1: Service Manual

    website:http://biz.LGservice.com LCD TV SERVICE MANUAL CHASSIS : LA74E MODEL : 20LS7D(C) 20LS7D(C)-UB CAUTION BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

  • Page 2: Table Of Contents

    CONTENTS CONTENTS ....................2 PRODUCT SAFETY ..................3 SPECIFICATION ..................6 ADJUSTMENT INSTRUCTION ...............10 TROUBLE SHOOTING ................14 BLOCK DIAGRAM...................19 EXPLODED VIEW ...................20 REPLACEMENT PARTS LIST ............... 22 SVC. SHEET ....................- 2 -...

  • Page 3: Product Safety

    SAFETY PRECAUTIONS IMPORTANT SAFETY NOTICE Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in 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 Shock, Fire, or other Hazards.

  • Page 4: Servicing Precautions

    SERVICING PRECAUTIONS CAUTION: Before servicing receivers covered by this service unit under test. manual and its supplements and addenda, read and follow the 2. After removing an electrical assembly equipped with ES SAFETY PRECAUTIONS on page 3 of this publication. devices, place the assembly on a conductive surface such as NOTE: If unforeseen circumstances create conflict between the aluminum foil, to prevent electrostatic charge buildup or...
  • Page 5 IC Remove/Replacement Some chassis circuit boards have slotted holes (oblong) through Circuit Board Foil Repair which the IC leads are inserted and then bent flat against the Excessive heat applied to the copper foil of any printed circuit circuit foil. When holes are the slotted type, the following technique board will weaken the adhesive that bonds the foil to the circuit should be used to remove and replace the IC.

  • Page 6: Specification

    SPECIFICATION NOTE : Specifications and others are subject to change without notice for improvement. 1. Application range 3. Test method 1) This spec sheet is applied all of the 20/23" LCD TV with 1) Performance : LGE TV test method followed LA74E chassis.
  • Page 7 5. Chroma & Brightness 5.1. FOR 23LC7D (CONDITION : EZ-Picture "Daylight") Item Unit White peak brightness cd/m cd/m Contrast ratio Refer to LCD SPEC. Brightness uniformity 1.25 Color coordinate Typ -0.03 0.638 Typ +0.03 Typ -0.03 0.337 Typ +0.03 GREEN Typ -0.03 0.299 Typ +0.03...
  • Page 8 5.1. FOR 20LC7D (CONDITION : EZ-Picture "Daylight") Item Unit Remark White peak brightness cd/m cd/m PSM : Daylight Contrast Ratio PSM : Daylight Brightness uniformity 1.25 Refer to LCD SPEC. Color coordinate 0.640 +/- 0.03 0.330 +/- 0.03 GREEN 0.290 +/- 0.03 0.600 +/- 0.03...
  • Page 9 7. RGB input (PC/DTV) Resolution H-freq(kHz) V-freq.(Hz) Pixel clock(MHz) Proposed 640*350 31.469 70.08 25.17 720*400 31.469 70.08 28.32 640*480 31.469 59.94 25.17 VESA(VGA) 800*600 37.879 60.31 40.00 VESA(SVGA) 1024*768 48.363 60.00 65.00 VESA(XGA) 1280*768 47.776 59.87 79.50 VESA(WXGA) 1360*768 47.712 60.01 85.50 VESA(WXGA)

  • Page 10: Adjustment Instruction

    ADJUSTMENT INSTRUCTION 1. Application Object 3-2. JIG Connection These instructions are applied to all of the LCD TV, LA74E. 2. Notes (1) Because this is not a hot chassis, it is not necessary to use an isolation transformer. However, the use of isolation transformer will help protect test equipment.
  • Page 11 3-4. Set Method 4. ADC-Set Adjustment (1) MCU Select: MTV512M64 4-1. Synopsis (2) Option R/W Option: Auto Write(Verity) ADC-Set adjustment to set the black level and the Gain to Jig Option: Myson optimum. Transmit Speed: Medium 4-2. Test Equipment (3) Check: Just do it with blank micom. (4) PORT Service R/C, 801GF(802V, 802F, 802R) or MSPG925FA Chose Parallel Port (normal LPT1)

  • Page 12: Edid Data

    (3) 23LS7D-UB : HDMI 5. EDID (The Extended Display Identification Data) EDID Block 0, Byte 0 - 127 [00H-7FH] / DDC Download (Display Data Channel) Block Type : EDID 1.3 This is the function that enables “Plug and Play". 00 FF FF FF FF FF FF 00 1E 6D 01 00 01 01 01 01 10 00 10 01 03 80 33 1D 96 0A CF 74 A3 57 4C B0 23 5-1.
  • Page 13 3. When G GAIN is set to 192 7. Adjustment of White Balance - Control R GAIN and B GAIN by lowering from 192. One of R Gain / G Gain / B Gain should be kept on 192, and adjust other two lower than 192.

  • Page 14: Troubleshooting

    TROUBLESHOOTING 1. TV/CATV doesn't display Could you measure voltage of Check TU4002 Pin9(Video output) You should check power line TU4002 & IIC lines? Can you see the normal signal? & IIC lines. Are they all normal? You should replace TUNER. Check the input(Pin63) of AV switch(IC5003).
  • Page 15 2. Video doesn't display Check J5007 Pin2 J5007 may have problem. Replace this Jack. Can you see the normal waveform? Check the input(Pin1) of AV switch (IC5003). After checking the Power of AV switch you should Pin1 is for video1,Pin8 is for video 2. decide to replace AV switch or not.
  • Page 16 3. Component doesn't display Check J5004 J5004 may have problem. Replace this Jack. Can you see the normal waveform? After checking the input TR of component, you Check the input of Component switch(IC5001). should decide to replace component switch or not. Can you see the normal waveform? After checking the Power of component switch Check the output of Component switch(IC5001).
  • Page 17 4. RGB_PC doesn't display Check input connect P7004. P7004 may have problem. Replace this Jack. Can you see the normal waveform? After checking the input TR of RGBHV, you Check the input of Component switch(IC5001). should decide to replace these components or Can you see the normal waveform? not.

  • Page 18: Hdmi Doesn't Display

    5. HDMI doesn't display Check input connect J7101. J7101 may have problem. Replace this Jack. Can you see the normal waveform? After checking the Power of this chip, you should Check DDC communication lines(IC702 Pin5,6) decide to replace this or not. After checking the Power of this chip, you should Check HDCP communication lines(IC701 Pin5,6) decide to replace this or not.

  • Page 19: Block Diagram

    BLOCK DIAGRAM CM2021 Tuner - 19 -...

  • Page 20: Exploded View

    EXPLODED VIEW - 20 -...

  • Page 21: Exploded View Parts List

    Cover MOLD HIPS 51SF LS1R HIPS 51SF LS1R-holder cable management EBR32575201 PCB Assembly,Main MAIN1 M.I LA63E 20LS2D . Broadcom EBU37686401 Main Total Assembly 20LS7DC-UB BRAND LA74E AGU32625902 Plate Assembly ASSY 20LS7D REAR SHIELD ASSY FOR DTV, US-CSKD EBR36026101 PCB Assembly,Sub CONTROL T.T LA74E 20LS7D BASIS Local key Total Ass’y...

  • Page 22: Replacement Parts List

    REPLACEMENT PARTS LIST DATE: 2007. 03. 10. LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION CAPACITORs C2002 0CK104BF56A C1005X7R104KET 100nF 10% 16V X7R -55TO+125 C2004 EAE30840301 10SVPC68M 68uF 20% 10V 1.97A -55TO+105C SV C1001 0CE107WF6DC MVK6.3TP16VC100M 100uF 20% 16V 80MA -40TO+ C2005...
  • Page 23 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION C2603 0CK103BH56A C1005X7R1E103KT- 10nF 10% 25V X7R -55TO+12 C3061 0CK104BF56A C1005X7R104KET 100nF 10% 16V X7R -55TO+125 C2604 0CK103BH56A C1005X7R1E103KT- 10nF 10% 25V X7R -55TO+12 C3062 0CK103BH56A C1005X7R1E103KT- 10nF 10% 25V X7R -55TO+12 C2605 0CK103BH56A...
  • Page 24 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION C4044 0CE107WF6DC MVK6.3TP16VC100M 100uF 20% 16V 80MA -40TO+ C5002 0CK103CK56A 0603B103K500CT 10nF 10% 50V X7R -55TO+125C C4046 0CK104BF56A C1005X7R104KET 100nF 10% 16V X7R -55TO+125 C5003 0CH3104K566 0805B104K500CT 100nF 10% 50V X7R -55TO+125 C4047 0CE107WF6DC...
  • Page 25 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION C6001 0CK105CD56A C1608X7R1A105KT 1uF 10% 10V X7R -55TO+125C C7170 0CE227WF6DC MVK8.0TP16VC220M 220uF 20% 16V 80MA -40TO+ C6002 0CK103BH56A C1005X7R1E103KT- 10nF 10% 25V X7R -55TO+12 C7170 EAE30840201 4SVPC330M 330uF 20% 4V 2.32A -55TO+105C SV C6003 0CK103BH56A...
  • Page 26 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION D4005 0DD184009AA KDS184 KDS184 TP KEC - 85V - - - 300MA KEC IC6001 0IPMG00063A MP1593DN-LF-Z 4.75TO28V 1.2V - SOIC R/TP 8 D4005 0DD184009AA KDS184 KDS184 TP KEC - 85V - - - 300MA KEC IC6004 0ITH638300C THC63LVDM83R 3VTO3.6V 500MW TSSOP R/TP 56P...
  • Page 27 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION AR2017 0RJ0222C692 MNR04 M0APJ 220 22OHM 5% 1/16W 1005X4 R/TP R1050 0RJ0000C678 MCR01MZPJ000 0OHM 5% 1/16W 1005 R/TP ROHM AR2200 EBC32260405 MNR04M0APJ680 68OHM 5% 1/16W 4P 8P R1051 0RJ0000C678 MCR01MZPJ000 0OHM 5% 1/16W 1005 R/TP ROHM...
  • Page 28 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION R1185 0RJ1000D677 MCR03EZPJ101 100OHM 5% 1/10W 1608 R/TP RO R3020 0RJ0000C678 MCR01MZPJ000 0OHM 5% 1/16W 1005 R/TP ROHM R1234 0RJ1000C678 MCR01MZPJ101 100OHM 5% 1/16W 1005 R/TP RO R3023 0RJ0000C678 MCR01MZPJ000 0OHM 5% 1/16W 1005 R/TP ROHM...
  • Page 29 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION R3203 0RJ0222C678 MCR01MZPJ220 22OHM 5% 1/16W 1005 R/TP - R R4080 0RJ4701C678 MCR01MZPJ472 4.7KOHM 5% 1/16W 1005 R/TP R R4000 0RJ1001C678 MCR01MZPJ102 1KOHM 5% 1/16W 1005 R/TP ROH R4082 0RJ0222C678 MCR01MZPJ220 22OHM 5% 1/16W 1005 R/TP - R...
  • Page 30 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION R4147 0RJ1001C678 MCR01MZPJ102 1KOHM 5% 1/16W 1005 R/TP ROH R5048 0RJ0822C678 MCR01MZPJ820 82OHM 5% 1/16W 1005 R/TP ROH R4147 0RJ1001C678 MCR01MZPJ102 1KOHM 5% 1/16W 1005 R/TP ROH R5049 0RJ1502D677 MCR03EZPJ153 15KOHM 5% 1/10W 1608 R/TP RO...
  • Page 31 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION R6031 0RJ0222C678 MCR01MZPJ220 22OHM 5% 1/16W 1005 R/TP - R R7114 0RJ1002D677 MCR03EZPJ103 10KOHM 5% 1/10W 1608 R/TP RO R6032 0RJ0222C678 MCR01MZPJ220 22OHM 5% 1/16W 1005 R/TP - R R7117 0RJ0822C678 MCR01MZPJ820 82OHM 5% 1/16W 1005 R/TP ROH...
  • Page 32 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION R7300 0RJ0332C678 MCR01MZPJ330 33OHM 5% 1/16W 1005 R/TP ROH L6003 EAP32842805 Inductor,Wire Wound,Chip NR8040T150M 15UH R7301 0RJ0682D677 MCR03EZPJ680 68OHM 5% 1/10W 1608 R/TP ROH L7008 0LCML00020B Inductor,Multilayer,Chip MLI-201209-6R8K 6.8UH R7302 0RJ0332C678...
  • Page 33 LOC. NO. PART NO. DESCRIPTION / SPECIFICATION LOC. NO. PART NO. DESCRIPTION / SPECIFICATION SW4002 140-058B EVQPB205K 1C1P 15VDC 0.02A VERTICAL 160GF SW4003 140-058B EVQPB205K 1C1P 15VDC 0.02A VERTICAL 160GF SW4004 140-058B EVQPB205K 1C1P 15VDC 0.02A VERTICAL 160GF SW4005 140-058B EVQPB205K 1C1P 15VDC 0.02A VERTICAL 160GF SW4006 140-058B...
  • Page 36 Mar., 2007 P/NO : MFL37186102 Printed in Korea...

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