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Directview LCD Training

9

Theory

TheOry

ThEORY

This section covers how an LCD Display works.

lIquId CRYSTAl dISPlAY

A Liquid Crystal Display is composed of a light source
(backlight), a Liquid Crystal Panel, and a driving circuit. We
start with a light source at the back of the panel composed of
thin fluorescent bulbs (CCFLs - Cold Cathode Flouresent Lamps).
This light passes through filters to help create a uniform light
source. Then the light passes through the Liquid Crystal Panel
which is composed of thousands of pixels that control the flow
of light throught the panel to make images.

Data Driver IC

Printed Circuit Board

Gate Driver IC

Inverter

Driving

Circuit

Power Supply

for Video Signal

Pixel Array & Wiring

Liquid Crystal

Panel

Polarizer
CF Panel
Liquid Crystal
TFT Panel

Lamp
Prism
Diffuser
Light Guide

Backlight Unit

Polarizer

Reflector

Inverter

Polarizer

TFT & Electrode

Color Filters

Top Electrode

Polarizer

Back Light

Liquid Crystals

Liquid Crystal Panel

Frame

Prism

Diffusers

Reflector

Light Guide

An LCD panel from a 15” LCD TV.

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Summary of Contents for 42LB4D

Page 1: ...LG TRAINING MANUAL 42LB4D LCD Fall 2007 LG TRAINING MANUAL ...

Page 2: ...eading must be infinite Any other abnormality that exists must be corrected before the receiver is returned to the customer Electrostatically Sensitive Devices Some semiconductor solid state devices can be damaged easily by static electricity Such components commonly are called Electrostatically Sensitive ES Devices Examples of typical ES devices are integrated circuits and some field effect trans...

Page 3: ...ower Supply flowchart 16 Troubleshooting Video 17 Video block diagram 17 No Video Flowchart 18 LCD Control Board 19 No RF Video Flowchart 21 No RF NTSC 22 No RF ATSC 23 AV1 AV2 Audio 24 Composite Video Input 25 Component Video Input 26 Component Input flowChart 27 RGB Video Input 28 HDMI SIGNAL PATH 29 Component RGB Flowchart 30 Defective Video Flowchart 31 Troubleshooting Audio 32 Audio signal pa...

Page 4: ... 4 ...

Page 5: ...i Features include USB Media Host and SimpLink USB Media Host consists of a USB port on the back of the TV that supports USB flash memory drives loaded with media or firmware for the TV SimpLink allows for control of other LG SimpLink products via the HDMI connection All LCD TV models are module level repair in and out of warranty They are covered by a one year parts and labor warranty Refer to th...

Page 6: ...t of Year and Month for Production March 2004 CALIBRATION MENU Input Pic Mode 1 Contrast 2 Brightness 3 Color 4 Tint 5 Sharpness 6 R Gain 7 G Gain 8 B Gain 9 R Offset 10 G Offset 11 B Offset POS SIZE ADJUST 1 H Position 2 V Position 3 H Size 4 V Size Default Load Count 6 90 50 50 0 50 192 97 147 64 64 64 0 0 0 0 DTV 1 2 3 7 8 9 4 6 5 0 FLASHBK EXPERT MODE Hold the MENU Key until ENTER PASSWORD app...

Page 7: ...OL To adjust the volume or accurately control a specific function 22 ENTER To set a specific function or complete setting 23 PIP CH OP1 To move the channel down in the PIP screen To use as a red key in the teletext mode 24 PIP CH OP2 To move the channel in the PIP screen To use as a green key in the teletext mode 25 PIP SWAP OP3 To switch between the main and sub screens To use as a yellow key in ...

Page 8: ... 8 ...

Page 9: ...ource Then the light passes through the Liquid Crystal Panel which is composed of thousands of pixels that control the flow of light throught the panel to make images Data Driver IC Printed Circuit Board Gate Driver IC Inverter Driving Circuit Power Supply for Video Signal Pixel Array Wiring Liquid Crystal Panel Polarizer CF Panel Liquid Crystal TFT Panel Lamp Prism Diffuser Light Guide Backlight ...

Page 10: ... polarizers are mounted at a 90 degree angle with respect to each other which prevents light from passing through The liquid crystals are used to twist the light beam 90 degrees and allow light to pass through that cell Color comes from a simple light filter Each sub pixel or cell a red green and blue sub pixel equals one pixel is controlled by a Thin Film Transistor TFT This provides accurate con...

Page 11: ... GND 12 6 11 0V 6V 11 3 2V 0V DIM 10 0V 0V GND 9 5V 5V 5Vs 8 2 753 0 22V BRI 7 3 2V 0V ERR 6 3 2V 0V I C 5 0V 0V GND 4 5V 5V 5Vs 3 3 0V 0V Von 2 5V 5V ACD 1 P201 Run Standby Connector 0V 0V GND 10 11 99 0V 12 9 0V 0V GND 8 3 46 0V 3 4 7 0V 0V GND 6 6 11 0V 6 5 0V 0V GND 4 0V 0V GND 3 18 86 0V 19 2 18 86 0V 19 1 P202 Run Stan dby Connector ...

Page 12: ...BL 24 12VDC 4 23 93V 0V VBL 24 12VDC 3 23 93V 0V VBL 24 12VDC 2 23 93V 0V VBL 24 12VDC 1 RUN mode Standby Label P205 BALLAST INVERTER 2 75V 0V VBR 2 7Vdc 13 3 23V 0V Von Off 3 2Vdc 12 3 27V 0V ADIM 3 2Vdc 11 0V 0V GND 10 0V 0V GND 9 0V 0V GND 8 0V 0V GND 7 0V 0V GND 6 23 93V 0V VBL 24 12VDC 5 23 93V 0V VBL 24 12VDC 4 23 93V 0V VBL 24 12VDC 3 23 93V 0V VBL 24 12VDC 2 23 93V 0V VBL 24 12VDC 1 Run Mo...

Page 13: ...ND 5 5 KOhm PWR_DN 1 KOhm 12V 7 KOhm 12V 0 GND 1 KOhm 12V 7 KOhm 12V 0 GND 0 GND 0 GND 5 5 MOhm 5V_STB 0 GND 0 GND 4 MOhm 5V_STB 0 GND 1 KOhm 3 4V c BT_CNTRL 0 GND 1 KOhm 3 4V 99 7 KOhm BT_CNTRL 1 KOhm 6V 0 GND c ERR_OUT 1 KOhm 6V 0 GND c ERR_OUT 1 KOhm 6V 1 3 KOhm 8V c INV_CTRL 1 KOhm 6V 1 KOhm 8V 93 4 KOhm INV_CTRL 0 GND 0 GND 0 GND 0 GND 0 GND 0 GND 0 GND 0 GND 8 MOhm STB 0 GND 0 GND 7 MOhm STB...

Page 14: ...V 1 8V ISL6549CB ISL6549CB 1 8V MK3727D MK3727D 74LVT16373 2EA 74LVT16373 2EA S29GL256 S29GL256 THC63LVD1023 THC63LVD1023 3 3V_L HYB18T512 4EA HYB18T512 4EA MK3727D MK3727D 19 0V 19 0V NTP3000 NTP3000 NTP3000 NTP3000 1 8V BA033FP 3 3 BA033FP 3 3 MTV416 MTV416 AZ1086 1 8 AZ1086 1 8 AZ1117H 3 3 AZ1117H 3 3 SC1565 2 5 SC1565 2 5 MST3369 MST3369 9 0V TEA6420 TEA6420 9 0V CS8416 CS8416 KIA78R09 KIA78R0...

Page 15: ...MI ADC MST3361 0X9C Temp Sensor LM75 0X94 U Com MTV416 0x50 I2C_CH1 3 3V_L 5V_L I2C_CH2 3 3V_L 5V_L I2C_CH3 3 3V_L Port Expander M62320 0X74 Audio Switch MSP4450K 0X80 DASP NTP3000 0X54 PDP Module 0x1C VSB QAM LGDT3703 Main 0X1C Live Dead CS8416A 0X20 W 0X21 R EEPROM 24LC512 0xA6 CH1 CH2 CH3 FRC94XYH 0xD4 EEPROM 24LC16 5V 5V 5V 2 5V ...

Page 16: ...al YES NO Replace MTV416GMF IC309 and Re download Check SI3865 MAIN PCB Q702 pin 2 3 5V Normal Replace Power board Check P702 MAIN PCB are all input voltages Normal YES Check SI3865 Q702 Pin 5 2 5V Normal NO NO Check P702 wafers Connectors Normal YES Check P701 MAIN PCB Pin 3 8 5V Normal YES Replace power board NO Replace SI3865 Q702 YES NO NO YES ...

Page 17: ...Video Scaler 0 Video Scaler 1 or 2 Active IC when in Standby mode Audio Video TP AV2 L R MNT Out L R COMP1 L R COMP2 L R RGB L R TP_IN1 AV1 AV2 AV1 Y C1 AV2 Y C2 Flash NOR 32MB Latchx2 24C512 Cable VSB LGDT3303 63LVD1023 1080P LVDS Con Dual AV1 L R GPIO I2S ATI X260 MPEG decoder COMP2 RGB CS8416 HDMI SPDIF I2S I2S MST3361 1HDMI 1ADC RGB HDMI1 2 3 SPDIF SPDIF Opt FRC94xyH DDR1 16MB RGB odd RGB even...

Page 18: ...Check THC63LVD1023 IC601 9 DE 15 Clk 7 Hsync 8 Vsync Check X260 IC101 Check P600 47 DISP_EN 33 TXAC 32 TXAC 17 TXBC 16 TXBC Check THC63LVD1023 IC601 Check LVDS Cable Check PDP LCD Module Control board 1 2 3 4 5 Y N Y Y Y Y N N LVDS Transmitter 47 DISP_EN 3 3V GND 33 TXAC 32 TXAC 17 TXBC 16 TXBC 74 25MHz 74 25MHz 74 25MHz 74 25MHz Clk 74 25MHz ...

Page 19: ...Directview LCD Training 19 Troubleshooting Video TROUBLESHOOTING LCD Control Board Video Data to LCD Panel Test points From LCD control board Video Data to LCD Panel Test points From LCD control board ...

Page 20: ...bleshooting Video TROUBLESHOOTING Check Video data from LVDS Transmitter IC601 The diagram shown points out the test points for the Video Data transmitted to the LCD Control PCB Points highlighted are above the LVDS cable connection ...

Page 21: ... Check LGDT3303 IC604 inputs power pins Osc 25Mhz IF pin Check LGDT3303 Outputs Check X260 INPUT CLK SOP Valid Error Data 1 Check Antenna cable RF switch Tuners 2 Check Tuners Vcc and IF out Appears to be noise 3 Check X260 Input CLK SOP Valid Error Data TPCLK TPSOP TPVALID nTPERR TPDATA 7 0 No RF Video Flowchart ...

Page 22: ...GB CVBS TP C TP B 656 AT NT TUNER LGDT 3303 VSB1 QAM TP MST 3361 HS VS DVI HS VS YCbCr2 YCbCr or RGB FRC9445H RGB CVBS YCbCr1 DVO Y C1 Y C2 Y C1 Y C2 AV1 2 AV1 2 HDMI 1 2 3 TMDS341A Check Antenna Cable Check Tuner 5V Video out Check X260 inputs M_TU_CVBS C2117 Check CVBS Video Path No RF NTSC ...

Page 23: ...A Comp1 2 RGB CVBS TP C TP B 656 AT NT TUNER LGDT 3303 VSB1 QAM TP MST 3361 HS VS DVI HS VS YCbCr2 YCbCr or RGB FRC9445H RGB CVBS YCbCr1 DVO Y C1 Y C2 Y C1 Y C2 AV1 2 AV1 2 HDMI 1 2 3 TMDS341A Check Antenna Cable Check Tuner 5V Video out Check X260 inputs M_TU_CVBS C2117 Check CVBS Video Path ...

Page 24: ...TROUBLESHOOTING AV1 AV2 Audio EXT 1 2 X260 TP A Comp1 2 RGB CVBS TP C TP B 656 AT NT TUNER LGDT 3303 VSB1 QAM TP MST 3361 HS VS DVI HS VS YCbCr2 YCbCr or RGB FRC9445H RGB CVBS YCbCr1 DVO Y C1 Y C2 Y C1 Y C2 AV1 2 AV1 2 HDMI 1 2 3 TMDS341A Audio Video ...

Page 25: ...o TROUBLESHOOTING Composite Video Input EXT 1 2 X260 TP A Comp1 2 RGB CVBS TP C TP B 656 AT NT TUNER LGDT 3303 VSB1 QAM TP MST 3361 HS VS DVI HS VS YCbCr2 YCbCr or RGB FRC9445H RGB CVBS YCbCr1 DVO Y C1 Y C2 Y C1 Y C2 AV1 2 AV1 2 HDMI 1 2 3 TMDS341A ...

Page 26: ...o TROUBLESHOOTING Component Video Input EXT 1 2 X260 TP A Comp1 2 RGB CVBS TP C TP B 656 AT NT TUNER LGDT 3303 VSB1 QAM TP MST 3361 HS VS DVI HS VS YCbCr2 YCbCr or RGB FRC9445H RGB CVBS YCbCr1 DVO Y C1 Y C2 Y C1 Y C2 AV1 2 AV1 2 HDMI 1 2 3 TMDS341A ...

Page 27: ...Cb_in 46 Cr_in 37 H 38 V 4 Check MST3361 IC402 Outputs V out 99 H out 98 Clock 96 Data 30Bit DE 97 5 Check X260 IC101 Inputs MST3361_HS T6 MST3361_VS T5 Clock P3 Data 30Bit DE U6 6 5 _Check the MST3361 IC402 Output Signals 4 _Check MST3361 IC402 Power pins Input Signals Signal Shape is same as above 6 _Check X260 IC101 Inputs 3 Check STMAV335 IC403 Signal shape is same as above Vsync DE Clk Hsync ...

Page 28: ...o TROUBLESHOOTING EXT 1 2 X260 TP A Comp1 2 RGB CVBS TP C TP B 656 AT NT TUNER LGDT 3303 VSB1 QAM TP MST 3361 HS VS DVI HSync VSync YCbCr2 YCbCr or RGB FRC9445H RGB CVBS YCbCr1 DVO Y C1 Y C2 Y C1 Y C2 AV1 2 AV1 2 HDMI 1 2 3 TMDS341A RGB Video Input ...

Page 29: ... TROUBLESHOOTING EXT 1 2 X260 TP A Comp1 2 RGB CVBS TP C TP B 656 AT NT TUNER LGDT 3303 VSB1 QAM TP MST 3361 HS VS DVI H Sync V Sync YCbCr2 YCbCr or RGB FRC9445H RGB CVBS YCbCr1 DVO Y C1 Y C2 Y C1 Y C2 AV1 2 AV1 2 HDMI 1 2 3 TMDS341A HDMI SIGNAL PATH ...

Page 30: ...4 Check MST3361 IC402 Outputs V out 99 H out 98 Clock 96 Data 30Bit DE 97 5 Check X260 IC101 Inputs MST3361_HS T6 MST3361_VS T5 Clock P3 Data 30Bit DE U6 6 5 _Check the MST3361 IC402 Output Signals 4 _Check MST3361 IC402 Power pins Input Signals Signal Shape is same as above 6 _Check X260 IC101 Inputs 3 Check STMAV335 IC403 Signal shape is same as above Vsync DE Clk Hsync 59 94Hz Data 1 Check Sign...

Page 31: ...1 IC402 inputs RX1C RX1C Vsync DE Clk Hsync 59 94H z Data 5 _Check X260 IC101 Inputs Snow noise White dot Power off and on TV or STB DVD Video is normal No Sound Check HDCP Power Pin IC404 MST3361 IC402 IIC 69 70 Check MST3361 IC402 inputs Power Osc 25 26 RX1C RX1C 14 15 RX0C RX0C Re download EDID IC406 407 408 Check MST3361 IC402 Outputs V out 99 H out 98 Clock 96 Data 1 2 3 4 N Y N Y Y Check X26...

Page 32: ...signal path EXT1 2 AT NT TUNER LGDT 3303 X260 TP A HDMI 1 2 3 TP C RGB COMP 1 2 SIF SIF IN 1 NTP 3000 SIF IN 2 I2S IN 1 I2S IN 2 I2S OUT 1 SPDIF 出 CS8416 I2S I2S I2S I2S S PDIF SPDIF L R L R L R L R ANT Cable VSB TP MSP4450K MNT OUT I2S I2S I2SI 3 I2SO 1 SC 2 MCLK MCLK SPDIF OUT Optical Coaxial ...

Page 33: ...MI input Check X260 IC101 Output R153 SCLK R154 LRCLK R155 DATA Check MSP4450K IC508 Input R5059 SCLK R5060 LRCLK R5061 DATA Check MNT Output Jack J704 Monitor L R Out Check MSP4450K IC508 Power 5 Check MSP4450K IC508 X tal Input X tal Input 71 72pin 18 432MHz 6 If ATV AV Component RGB input Check MSP4450K IC508 Input C5016 ATV_SIF R5041 AV1_R R5042 AV1_L R5045 AV2_R R5046 AV2_L R5048 CMP1_R R5049...

Page 34: ... LGDT 3303 X260 TP A HDMI 1 2 3 TP C SIF SIF IN 1 NTP 3000 SIF IN 2 I2S IN 1 I2S IN 2 I2S OUT 1 SPDIF 出 CS8416 I2S I2S I2S I2S S PDIF SPDIF ANT Cable VSB TP I2S I2S I2SI 3 I2SO 1 MCLK MCLK SPDIF OUT Optical Coaxial EXT1 2 RGB COMP 1 2 SIF L R L R L R L R MSP4450K MNT OUT I2SI 3 I2SO 1 SC 2 ...

Page 35: ...508 inputs C5016 67pin 1 2 3 4 5 6 Follow the procedure of COMMON SOUND OUT 7 8 Check Tuner TU600 5V 3 5 9 17 pin SIF 18 pin Check Antenna Cable Check X260 IC101 Intputs R175 SCLK R176 LRCLK R177 DATA Check MSP4450K IC508 Power Check MSP4450K IC508 outputs R5039 SCLK R5040 LRCLK R5043 DATA No RF Sound flowchart ...

Page 36: ...T1 2 AT NT TUNER LGDT 3303 X260 TP A HDMI 1 2 3 TP C RGB COMP 1 2 SIF SIF IN 1 NTP 3000 SIF IN 2 I2S IN 1 I2S IN 2 I2S OUT 1 SPDIF 出 CS8416 I2S I2S I2S I2S S PDIF SPDIF L R L R L R L R ANT Cable VSB TP MSP4450K MNT OUT I2S I2S I2SI 3 I2SO 1 SC 2 MCLK MCLK SPDIF OUT Optical Coaxial ...

Page 37: ...s EXT1 2 AT NT TUNER LGDT 3303 X260 TP A TP C RGB COMP 1 2 SIF SIF IN 1 NTP 3000 SIF IN 2 I2S IN 1 I2S IN 2 I2S OUT 1 SPDIF 出 CS8416 I2S I2S I2S I2S S PDIF SPDIF L R L R L R L R ANT Cable VSB TP MSP4450K MNT OUT I2S I2S I2SI 3 I2SO 1 SC 2 MCLK MCLK SPDIF OUT Optical Coaxial HDMI 1 2 3 ...

Page 38: ...PDIF 出 CS8416 I2S I2S I2S I2S S PDIF SPDIF L R L R L R L R ANT Cable VSB TP MSP4450K MNT OUT I2S I2S I2SI 3 I2SO 1 SC 2 MCLK MCLK Optical Coaxial HDMI 1 2 3 Check CS8416 IC501 inputs HDMI_SPDIF C5005 Follow the procedure of COMMON SOUND OUT Check MST3361 IC402 output HDMI_SPDIF R409 Check HDMI Cable Check X260 IC101 Inputs SCLK R175 LRCLK R176 DATA R177 Check CS8416 IC501 outputs DATA 26 SCLK 27 L...

Page 39: ...Check VBUS_5V Check the DC DC Converter IC712 N Y Y N N 2 Check Sequence Change the cable to USB1 1 cable or Replace the device Y N Replace the DC DC Converter IC712 Exception USB power could be disabled by inrushing current In this case remove the device and try to reboot the TV AC power off on X260 USB_ link IC101 DC DC Converter IC712 J A C K Side B D USB1 1_OVRCUR 5V_USB VBUS_5V DP DM Cable US...

Page 40: ...Directview LCD Training 40 Disassembly Disassembly 300 806 803 200 530 120 500 807 802 121 520 510 550 805 400 810 804 610 600 800 910 900 540 801 Disassembly Exploded View ...

Page 41: ...901303 801 Plate PRESS EGI 1 2 FRAME SBHG A 37LY3 METAL BAR TOP C SKD MGJ32901202 800 Main Total Assembly 37LB4DS UA BRAND AUSLLHX EBU35305401 610 SMPS AC DC LGLP 3237 HEP 90VTO264V 210W 47 63 UL CSA SEMKO HE AT YY 3 EAY33064501 600 PCB Assembly Sub SUB T T LA73A 37LB4DS UA AUSLLHX 37LB4DS UA Side AV total EBR35342501 550 PCB Assembly Sub SUB T T LA71A 42LY3DR NA AKRLLH AC Inlet Ass y Total EBR365...

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