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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.
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CONTENTS CONTENTS .............................................................................................. 2 PRODUCT SAFETY ..................................................................................3 SPECIFICATION ........................................................................................6 ADJUSTMENT INSTRUCTION ...............................................................10 TROUBLE SHOOTING ............................................................................
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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. Do not modify the original design without permission of manufacturer. Leakage Current Hot Check (See belo
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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 following servicing precautions and any of the safety
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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. When working with board causing the foil to separate from or "lift-off" the bo
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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. 2) Demanded other specification 2) Not included spec and each product spec in this spec sheet Safety : UL, CSA, IEC specification apply correspondingly to the following each country EMC : FCC, ICES, IEC specification standard and requirem
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5. Chroma & Brightness 5.1. FOR 23LC7D (CONDITION : EZ-Picture "Daylight") No Item Min Typ Max Unit 1 White peak brightness 360 450 cd/m 260 450 cd/m 2 Contrast ratio 550 700 400 700 Refer to LCD SPEC. 3 Brightness uniformity 1.25 4 Color coordinate RED X Typ -0.03 0.638 Typ +0.03 5 Y Typ -0.03 0.337 Typ +0.03 6 GREEN X Typ -0.03 0.299 Typ +0.03 7 Y Typ -0.03 0.604 Typ +0.03 8 BLUE X Typ -0.03 0.145 Typ +0.03 9 Y Typ -0.03 0.059 Typ +0.03 10 WHITE X Typ -0.03 0.280 Typ +0.03 11 Y Typ -0.03 0.292
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5.1. FOR 20LC7D (CONDITION : EZ-Picture "Daylight") No Item Min Typ Max Unit Remark 2 1. White peak brightness 360 450 cd/m 2 250 450 cd/m PSM : Daylight 2. Contrast Ratio 600 700 400 700 PSM : Daylight 3. Brightness uniformity 1.25 Refer to LCD SPEC. 4. Color coordinate RED X 0.640 +/- 0.03 Y 0.330 +/- 0.03 GREEN X 0.290 +/- 0.03 Y 0.600 +/- 0.03 BLUE X 0.150 +/- 0.03 Y 0.060 +/- 0.03 WHITE X 0.295 +/- 0.03 Y 0.305 +/- 0.03 5. White Balance Target Cool X 0.274 +/- 0.015 Y 0.274 +/- 0.015 Medium
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7. RGB input (PC/DTV) No Resolution H-freq(kHz) V-freq.(Hz) Pixel clock(MHz) Proposed PC 1 640*350 31.469 70.08 25.17 DOS O 2 720*400 31.469 70.08 28.32 DOS O 3 640*480 31.469 59.94 25.17 VESA(VGA) O 4 800*600 37.879 60.31 40.00 VESA(SVGA) O 5 1024*768 48.363 60.00 65.00 VESA(XGA) O 6 1280*768 47.776 59.87 79.50 VESA(WXGA) O 7 1360*768 47.712 60.01 85.50 VESA(WXGA) O 8 1366*768 60.023 60.00 80.00 8. Mechanical specification <20LC7D> No. Item Content Remark 1 Product Dimension Width(W) Length(D)
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ADJUSTMENT INSTRUCTION 3-2. JIG Connection 1. Application Object 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. (2) Adjustments must be done in the correct order. (3) The adjustments must be performed in the circumstance of 20±5°C of temperature and 65±10% of relative humidity if there is no specific designat
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3-4. Set Method 4. ADC-Set Adjustment (1) MCU Select: MTV512M64 (2) Option 4-1. Synopsis 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 (3) Check: Just do it with blank micom. 4-2. Test Equipment (4) PORT Service R/C, 801GF(802V, 802F, 802R) or MSPG925FA Chose Parallel Port (normal LPT1) Pattern Generator Attention:You must chose EPP when select Rom BIAS at LPT (480i/1080i The Horizontal 100% Color Bar
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(3) 23LS7D-UB : HDMI 5. EDID (The Extended Display Identification Data) EDID Block 0, Byte 0 - 127 [00H-7FH] / DDC (Display Data Channel) Download Block Type : EDID 1.3 0123456789 A B C D E F This is the function that enables “Plug and Play". 0 00 FFFFFFFFFFFF 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. HDMI EDID Data Input 20 09 48 4C 2F CE 00 31 40 45 40 61 40 01 01 01 01 30 01 01 01 01 01 01 66 21 50 B0 51 00 1B 30 40 70 (1) Required Test Equipment 40 36
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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. 7-1. Required Equipment (When R/G/B GAIN are all 192, it is the FULL DYNAMIC (1) Color analyzer (CA-100 or CA210 similar product) Range of Module) (2) Automatic adjustor (with automatic adjustment necessity and the RS-232C communication being possible) 7-2. Connection Diagram of Equipment for Mea
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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. No No Are they all normal? Yes Yes You should replace TUNER. Check the input(Pin63) of AV switch(IC5003). After checking the Power of AV switch you should Can you see the normal waveform? decide to replace AV switch or not. No Yes Check the output(Pin56) of AV switch(IC5003). After checking the Power o
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2. Video doesn't display Check J5007 Pin2 J5007 may have problem. Replace this Jack. Can you see the normal waveform? No Yes 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. No Can you see the normal waveform? Yes Check the output(Pin56) of AV switch(IC5003). After checking the Power of AV switch you should Can you see the normal waveform? decide to replace AV switch or not.
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3. Component doesn't display Check J5004 J5004 may have problem. Replace this Jack. Can you see the normal waveform? No Yes After checking the input TR of component, you Check the input of Component switch(IC5001). should decide to replace component switch or not. No Can you see the normal waveform? Yes After checking the Power of component switch Check the output of Component switch(IC5001). you should decide to replace component switch or Can you see the normal waveform? No not. Yes After chec
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4. RGB_PC doesn't display Check input connect P7004. P7004 may have problem. Replace this Jack. Can you see the normal waveform? No Yes After checking the input TR of RGBHV, you Check the input of Component switch(IC5001). should decide to replace these components or No Can you see the normal waveform? not. Yes Check the output of Component switch(IC5001). After checking the Power of RGB switch you Can you see the normal waveform? should decide to replace component switch or not. No Yes Check t
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5. HDMI doesn't display Check input connect J7101. J7101 may have problem. Replace this Jack. Can you see the normal waveform? No Yes After checking the Power of this chip, you should Check DDC communication lines(IC702 Pin5,6) decide to replace this or not. No Yes After checking the Power of this chip, you should Check HDCP communication lines(IC701 Pin5,6) decide to replace this or not. No Yes Check the input of MST3382M(IC7012). After checking the trace of TMDS lines and power This signal i
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BLOCK DIAGRAM CM2021 - 19 - 3.3V 2.6V SC1566 P4004 9V 3.3VST_MICOM CVBS RS-232 LIVE_ON 5.0V 6.0V MAIN Y CXA2069Q PQ05DZ ST5V EEPROM KIA7029 6.0V SVHS M_YC FMS6400S (IC5003) MAIN_C (IC4006) ST5V PWM_DIM IC3232 9.0V 3.3VST_MICOM KA7809A P4007 PDD/ INV 12.0V BCM_Rx Tx UC OM_Rx Tx KEY1 RGB_LR 9V 5V 5V_MNT 1.2V 3.3V KEY2 SC4519S INV_ON MTV416GMF MC33078DR C55331A IR I2C_3 AUO_LR ST_5V (IC4015) (IC7002) (IC7001) 3.3V LRD_G 5.0V AL_ON AZ1117H LRD_R AC_DET COM_LR 3.3VST ST 5.0V 5V_TU BA033FP AT_TU_V KIA
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