LG 26LH1DC1-UB Service Manual Download Page 1

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LCD TV

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

MODELS :

26LH1DC1-UB

website:http://biz.LGservice.com

e-mail:http://www.LGEservice.com/techsup.html

December, 2007

P/NO : 3350GDKM0020A

Internal Use Only

Summary of Contents for 26LH1DC1-UB

Page 1: ...CAUTION BEFORE SERVICING THE CHASSIS READ THE SAFETY PRECAUTIONS IN THIS MANUAL MODELS 26LH1DC1 UB website http biz LGservice com e mail http www LGEservice com techsup html December 2007 P NO 3350GDKM0020A Internal Use Only ...

Page 2: ... purposes CONTENTS CONTENTS 2 SAFETY PRECAUTIONS 3 SPECIFICATION 6 ADJUSTMENT INSTRUCTION 11 SVC REMOCON 21 TROUBLE SHOOTING GUIDES 22 TROUBLE SHOOTING 24 BLOCK DIAGRAM 27 VIDEO AND AUDIO SIGNAL FLOW CHART 34 WIRING DIAGRAM 46 EXPLODED VIEW 47 EXPLODED VIEW PARTS LIST 48 REPLACEMENT PARTS LIST 49 SVC SHEET ...

Page 3: ...fe to operate without damage of electrical shock Leakage Current Cold Check Antenna Cold Check With the instrument AC plug removed from AC source connect an electrical jumper across the two AC plug prongs Place the AC switch in the on position connect one lead of ohm meter to the AC plug prongs tied together and touch other ohm meter lead in turn to each exposed metallic parts such as antenna term...

Page 4: ...e on your body by touching a known earth ground Alternatively obtain and wear a commercially available discharging wrist strap device which should be removed to prevent potential shock reasons prior to applying power to the unit under test 2 After removing an electrical assembly equipped with ES devices place the assembly on a conductive surface such as aluminum foil to prevent electrostatic charg...

Page 5: ...the solder joints of the two original leads If they are not shiny reheat them and if necessary apply additional solder Fuse and Conventional Resistor Removal Replacement 1 Clip each fuse or resistor lead at top of the circuit board hollow stake 2 Securely crimp the leads of replacement component around notch at stake top 3 Solder the connections CAUTION Maintain original spacing between the replac...

Page 6: ...tem Digital ATSC 64 256QAM Analog NTSC Sound Effect Dolby Digital AC 3 Available Channel Air CH2 CH69 Cable CH1 CH135 Input Voltage AC 100 240V 50 60Hz Market North America Screen Size 26 inch Wide Aspect Ratio 16 9 Tuning System FS LCD Module LC260WX2 SLB2 LPL LC260WX2 SLB1 LPL LC260WX2 SLA1 LPL Video Stream Compression MPEG2 MP HL Receiving Signal 8VSB Clear QAM 64 256 NTSC Display Interface LVD...

Page 7: ...st 0 2 0 1usec 90 2 dB 180 2 Static Ghost 0 2 0 2usec 90 2 dB 180 2 Static Ghost 0 2 0 3usec 90 2 dB 180 2 Static Ghost 0 2 1 0usec 90 2 dB 180 2 Static Ghost 0 2 5 0usec 90 2 dB 180 2 Doppler Ghost 0 2Hz 4 0 1 usec 0 5Hz 4 1 0Hz 4 dB 2 0Hz 4 5 0Hz 4 Doppler Ghost 0 2Hz 4 0 2 usec 0 5Hz 4 1 0Hz 4 dB 2 0Hz 4 5 0Hz 4 Item Specification Unit Remark 4 DTV Characteristics 4 1 General Specification 4 2 ...

Page 8: ...00Hz 25kHz Dev 256 QAM 16 dB DTV 40dBm 4 3 Digital Receive Part 64 256 QAM Input CVBS 1V 480i Active Video mV 644 714 786 Sync 258 286 314 S Video 1V Active Video mV 644 714 786 Sync 258 286 314 Color Burst 258 286 314 Component 1V 480i 480p 720p 1080i Y Pb Pr mV 630 700 770 Sync 270 300 330 RGB Input DTV 480i 480p 720p 1080i R G B mV 630 700 770 PC See 5 Signal Timing H V TTL 4 4 Video Inputs 4 5...

Page 9: ...17 EGA 2 720 400 31 469 70 087 28 32 DOS 3 640 480 31 469 59 94 25 175 VGA 4 640 480 37 5 75 31 5 VGA 5 640 480 43 269 85 008 36 VGA 6 800 600 37 879 60 317 40 SVGA 7 800 600 46 875 75 49 5 SVGA 8 800 600 53 674 85 061 56 25 SVGA 9 832 624 49 726 75 552 58 05 MAC 10 1024 768 48 363 60 004 65 XGA 11 1024 768 60 023 75 029 78 75 XGA 12 1024 768 68 677 84 997 94 5 XGA 13 1280 720 44 772 59 855 74 5 V...

Page 10: ...0 48 077 72 18 50 SVGA 8 800 600 46 875 75 49 5 SVGA 9 800 600 53 7 85 56 25 SVGA 10 1024 768 48 363 60 65 XGA 11 1024 768 56 476 70 06 75 XGA 12 1024 768 60 023 75 02 78 75 XGA 13 1024 768 68 7 85 94 5 XGA 14 1280 768 47 78 59 87 79 5 15 1360 768 47 72 59 8 84 75 16 720 400 31 43 70 27 28 DOS 17 720 480 15 75 60 27 03 SDTV 480i 18 720 480 15 734 59 94 27 SDTV 480i 19 720 480 31 5 60 31 5 SDTV 480...

Page 11: ...ion includes Version Date Model name and Panel information 3 Chip I2 C Test It shows you whether there is any issue in the HW of the major Device on the Board at its basic level 4 Aging Test When you press Confirm the service menu OSD temporarily disappears and single color Pattern is displayed When you press ENTER key it returns to its original condition 5 White Balance Control the offset gain of...

Page 12: ...his is the item to adjust the brightness of the panel The default set value is 70 and can be adjusted to between 1 and 100 When the value is set to 1 it is the lowest value 20 and when set to 100 it is the highest brightness 100 The PWM signal sent out from MICOM is converted to DC voltage to adjust the brightness of the panel As a reference the DC voltage value sent out from the board according t...

Page 13: ...on the back of the TV in the direction of NORMAL DTV 3 With the RS 232C Cable connect the RS 232C port of the TV and the COM port of the PC 4 Execute the KMCOMM exe program on the PC 5 After checking the port number connected to the TV from Control Panel System Hardware Device Manager Ports set the Port for the Connection group 6 Check whether the Model of the Configuration group is set to SupraHD...

Page 14: ...hecking the port number connected to the TV from Control Panel System Hardware Device Manager Ports set the Port for the Connect using 7 Set 115200 for Bit per second 8 for Data bits None for Parity 1 for Stop bits None for Flow control and then click on OK button 8 Check if the Hyper Terminal is connected Turn on the TV while pressing the UPDATE SWITCH on the rear part of TV and check the followi...

Page 15: ...r 2 256QAM But you must not set 64QAM 256QAM for Air After completing the all the settings select upgrade start to start the upgrade When all the upgrade is normally completed the system will automatically reboot Even if it fails you must turn the power off and then turn it back on to return to its normal condition 4 EDID Data Write RGB PC port HDMI port EDID down load Read Write Required equipmen...

Page 16: ... 00 48 44 54 56 20 20 20 20 20 20 20 20 0A 01 E5 00000080 02 03 1B F2 44 85 84 03 07 26 09 07 07 15 07 50 00000090 83 01 00 00 66 03 0C 00 10 00 80 01 1D 80 18 71 000000A0 1C 16 20 58 2C 25 00 C4 8E 21 00 00 9E 01 1D 00 000000B0 72 51 D0 1E 20 6E 28 55 00 C4 8E 21 00 00 1E 8C 000000C0 0A D0 8A 20 E0 2D 10 10 3E 96 00 C4 8E 21 00 00 000000D0 18 8C 0A A0 14 51 F0 16 00 26 7C 43 00 C4 8E 21 000000E0 ...

Page 17: ...ume setting 010 MUTE DISABLE 000 1 000 Set to 1 to disable mute function 011 KEY DEFEAT 000 1 000 Disables menu navigation keys on display panel 015 SLEEP TIMER 000 1 001 Set to 1 to enable Sleep Timer 016 EN TIMER 000 1 000 Set to 1 to enable On Off Timers 017 ALARM 000 1 001 Set to 1 to enable Alarm 021 V CHIP 000 1 001 Set to 1 to enable V Chip functions 022 MAX BLK HRS 000 99 012 Sets number o...

Page 18: ...000 2 002 Enables RGB2 input Set to 1 for DTV or 2 for PC Set to 0 to disable 093 RJP AVAILABLE 000 1 000 Set to 1 to enable 094 SAP MENU EN 000 1 001 Set to 0 to disable feature on Function menu Set 1 to enable feature on Function menu 096 DEF ASP RATIO 000 134 002 Sets default aspect ratio at power up See detailed descriptions and item 106 101 IR BLASTER N A N A Not applicable 102 ATSC BAND 000 ...

Page 19: ...lti Track Stereo Internal Speaker On 3 Channel Antenna Only Item display Auto Memorizing Yes Channel Label Default Channel List Empty Fine Tune Auto Signal Strength DTV Only 4 Setup Time Clock Manual Manual Clock Daylight Saving Yes Time Zone Eastern On Timer Only Item display Off Timer Only Item display Auto Off Off V Chip Please Enter your PIN 0000 Default Changing PIN New PIN Confirm PIN On Off...

Page 20: ... 60 Gain Pb 60 Gain Pr 60 Reset Mode 7 RGB offset gain Offset R 128 Offset G 128 Offset B 128 Gain R ADJ Value 128 Gain G ADJ Value 128 Gain B ADJ Value 128 Reset Mode 8 Auto Picture Auto Brightness ADJ Value 50 Auto Contrast 91 9 Running Time Running Time HOURS Reset Mode 10 System All Reset Confirm 11 Audio Delay DTV 0 ATV CVBS YC 0 COMP PC HDMI 0 12 AI Control OFF 13 Last Power Save ON 14 Panel...

Page 21: ...sound according to the program type To check component input To check the front AV To move channel up down or to select a function displayed on the screen To adjust the volume or accurately control a specific function To set a specific function or complete setting N A N A N A N A N A To select the functions such as picture sound channel setup caption To set the delivery condition status after manu...

Page 22: ... Main Board Replace External equipment Cable Check Replace Main Board Replace External equipment Cable Check Replace Main Board Replace Speaker Cable Check Replace Check for problems in audio MICOM Check the operation Main Board Replace Is it communicating with the Service Port Is the screen color normal Is the color normal when PC HDMI is selected Is the color normal when External Input S Video C...

Page 23: ...of the DDR memory When the booting flow is normally written in the debugger window of the PC but rebooting check the communications line SCL1 SDA1 of MICOM IC705 and main chip IC401 4 Check whether the digital broadcasting is normally received If it is not normally received check the following Measure the power of no 3 pin of TUNER IC105 TU5V Measure the power of no 12 pin of TUNER IC105 TU3 3V Me...

Page 24: ... LVDS cable connected well Reset Cable Replace LVDS Cable Check Power On signal Is the Power On Signal correct Check Key Pad IR Input Check Power Supply Is LCD Voltage 24V 12V normal Check Power Supply Video Normal on Analog RF Check TUNER Video normal on Video3 Check HC4051 Video normal on DIGITAL RF Check TUNER Video normal on AutoCamport AV2 Check RJP Mode Check HC4051 YES YES YES YES YES YES Y...

Page 25: ...le Replace LVDS Cable Is LED D102 lighted Check the Main Board Check Key Pad IR Input Replace Key Pad or IR Input Check Power Supply YES YES YES YES NO NO NO NO 3 No Power Symptom Front LED is OFF and no picture Check Flow Power cord connected Plug in Power cord Replace Fuse T5 0A H 250V Is the Power Board connected to each control Board When ST BY 12V 5V does not operate replace Power Board Conne...

Page 26: ...cable connected well Reset Cable Replace Speaker Cable Audio Voltage 12V normal Audio normal on HDMI Check Power Supply Audio normal on DIGITAL RF Check EDID EEPROM Audio normal on Analog RF Check MSP3425 Audio normal on Video3 Check TEA6422D Audio normal on DIGITAL RF Check TUNER Audio normal on AutoCamport AV2 Check RJP Mode Check TEA6422D YES YES YES YES YES YES YES YES YES YES NO NO NO Check S...

Page 27: ...3728 MHz ISOLATED SERIAL DATA INTERFACE ISOLATED OUTPUT TRANSFORMER 8 OHM 2W ISOLATED DC DC CONVERTER 12VDC OUT ST12V ST12V 12VA 12V ST12V ST5V 24V REMOTE CONTROL I C 2 I C 2 I C 2 Digital Pillow Speaker SPEAKER OUT SPEAKER SELECTOR SPEAKER OUT IC708 STA323W IC401 ZR39660 IC708 STA323W IC401 ZR39660 IC705 M37151 IC705 M37151 IC302 RTD2023B IC201 MST9883 IC302 RTD2023B IC201 MST9883 IC707 BA7657 IC...

Page 28: ...LINE FILTER MAIN CONTROL IC802 PSU PWR ON OFF Q803 STAND BY CONTROL IC900 OPTO COUPLER IC807 ACTIVE HIGH 24V 4 5A 12V 2 5A ST 12V 1 25A ST 5V 0 1A PWR CTL A 12V 2 0A STAND BY TRANS T901 MAIN TRANS T801 RECTIFIER SCHOTTKY RECTIFIER SCHOTTKY 5V REGULATOR U201 FEED BACK IC804 FEED BACK IC902 BRIDGE BD801 PFC IC801 DC 400V POWER SUPPLY ...

Page 29: ...24V KA7809 DC DC FDS4435 12V SMPS 12VA ST5V ST12V 24V MSP3425 40mA TEA6422 10mA MC33078 10mA M37151 Tuner 10mA Tuner 340mA MSP3425 74HC4051 FMS6143 TS5V330D HD660 1 1A RTD2023B 80mA RTD2023B 50mA MST9883 100mA HD660 300mA STA323W AM29LV320 50mA MST9883 100mA RTD2023B 230mA W24C256 SP3232 30mA HD660 50mA K4H281638D x 2 300mA RTD2023B 80mA LCD Panel 450mA Logic STA323W 2A Tuner 225mA MC9S12E128CFU L...

Page 30: ... LG Electronics Inc All right reserved 30 LGE Internal Use Only Only for training and service purposes SupraHD 660 IC Block Diagram Note The SupraHD 680 has an integrated CableCard controller the SupraHD 660 does not ...

Page 31: ...or the ATSC Market SupraHD 640 IC ZR39640 Digital ATSC upgrade for Analog TVs 2 SupraHD 660 680 IC Description The SupraHD 660 680 ICs are members of the SupraHD family of DTV controllers developed by Zoran These devices are intended to be used in ATSC compliant television implementations They add the functionality required to support OpenCable implementations These devices include all of the func...

Page 32: ... Inc All right reserved 32 LGE Internal Use Only Only for training and service purposes Figure 3 shows a typical system implementation using the SupraHD 660 680 This system can be designed and manufactured in a very low cost manner ...

Page 33: ...7 LG Electronics Inc All right reserved 33 LGE Internal Use Only Only for training and service purposes 3 I O Options Figure 4 shows the four major I O options available video input and output audio input and output ...

Page 34: ...This signal is transferred to the FPGA chip of IC901 FPGA chip decrypts the TS data so that it can be decoded by the DTV decoder in the next terminal The TS data decrypted by IC901 is decoded by the video decoder of DTV controller of IC401 and converted to the LVDS signal The LVDS signal is transferred to the LCD panel through the P503 connector to be displayed on the LCD panel Tuner ATSC QAM Vide...

Page 35: ...signal ATSC QAM received in the input terminal of the tuner is converted to the base band signal in the tuner IC105 to send out 8 bit transport stream This signal includes both the video and audio signal The audio received by the DTV controller through IC901 is decoded for Dolby AC3 in the audio decoder and the PCM data is transferred in I2 S format This signal is converted to stereo signal L R fr...

Page 36: ...d by IC706 which is the analog video switch The analog video switch receives the CVBS signal sent from the tuner and the external signal AV1 AV2 AV3 S Video caption and Component caption signal and sends out one of the signals The external input mode selected by the TV AV button on the remote controller is the video signal selected for output The output signal is the decoded in the DTV controller ...

Page 37: ... input terminal of the tuner IC105 is sent out as the sound IF signal by the tuner The SIF signal goes through Automatic Volume Correction AVC in the audio processor and sent to the OP Amp IC603 This signal is amplified to be sent to the audio processor again The audio processor converts the stereo signal into I2 S format to send to DTV controller and PCM data is outputted in I2 S format through a...

Page 38: ...ved through the RCA jack of P703 and AV2 is received through the 6 pin wafer of CN105 These signals all come to the analog video switch IC706 and only 1 signal is selected In other words it is the same as the analog RF signal The one signal that has been selected for output is decoded in the DTV controller and converted to LVDS signal to be sent to the LCD panel through the LVSD connector P503 Als...

Page 39: ...nd CN105 and the AV3 uses the same audio terminal as S Video One stereo signal among the signals received through the audio switch IC601 to send to the audio process IC602 The Audio switch receives the audio input signal of AV1 AV2 AV3 S Video and component1 component2 PC DVI to select and output one stereo signal The stereo signal selected this way is converted to I2 S format in the audio process...

Page 40: ...7 SD Video Filter IC705 Micro Processor P503 LVDS Connector P101 S Video Jack S Video signal is received through P101 jack Y signal and C signal are separated in this signal and is received directly by DTV controller IC401 and decoded by IC401 to convert to LVDS signal Then it is sent to the LCD panel through P503 And the caption signal is send to IC401 through the video filter IC107 and microproc...

Page 41: ...Video Filter P503 LVDS Connector P201 RCA Jack One of the component1 and 2 video signals received in P201 is selected by the video switch IC202 and sent to Analog to Digital converter IC201 The analog signal received in IC201 is converted to the digital signal and sent as output in 24 bit The digital signal of 24bit is received in DTV controller IC401 and decoded to convert to LVDS signal and sent...

Page 42: ... signal of component1 and component2 is received in P601 and sent to the audio switch IC601 One stereo signal is selected among the received signals in the audio switch IC601 and sent to the audio process IC602 The stereo signal selected is converted to I2 S format through the audio processor and sent to the DTV controller to be sent as output in I2 S format through the audio decoding process This...

Page 43: ...s the EDID information of IC303 through I2 C line and outputs the best resolution supported by this board When the EDID information is not recorded in NVRAM IC303 or when the EDID information cannot be read due to communications line issue basic resolution provided in PC is sent out as output The analog RGB signal entered through IC302 is converted to AD through the scaler IC302 and sent to IC401 ...

Page 44: ...io signal or DVI audio signal is received in P602 to be sent to the audio switch IC601 One stereo signal among the signal received by the audio switch IC601 is selected and sent to the audio process IC602 Selected stereo signal is converted to I2 S format by audio processor to be sent to DTV controller and outputted in I2 S format through audio decoding process This signal is converted to stereo s...

Page 45: ...smitter does not send out the video and audio signal When HDCP certification is successfully done the signal sent by the transmitter that could not read the EDID information is decoded by the DTV controller IC401 and converted to LVDS signal to be sent to the LCD panel through the LVDS connector The DVI transmitter only outputs the video signal after HDCP certification and reading the EDID informa...

Page 47: ...Copyright 2007 LG Electronics Inc All right reserved 47 LGE Internal Use Only Only for training and service purposes EXPLODED VIEW MODEL NO 26LH1DC1 UB 1 11 12 13 14 15 16 17 18 19 20 2 3 4 5 6 7 8 9 10 ...

Page 48: ...e_Rear AV Label_Serial Label_Dolby Label_ID Spec Speaker Harness Speaker Harness Chassis_PCB Supporter Chassis_PCB Guide Cover_MPI Card Plate_MPI Card Nut_Stamped_Locking MPI Card Board 204 3460 00 MPI Connector Board 6367T_MCN Main Board Gap Pad Gasket_EMI Service Board Gasket_EMI Harness Cover_Side Jack Plate_Side AV Cover_Front Silver Assembly 26 LCD Panel LC260WX2 SLB2 Chassis_Main Assembly Po...

Page 72: ...CAUTION BEFORE SERVICING THE CHASSIS READ THE SAFETY PRECAUTIONS IN THIS MANUAL MODELS 26LH1DC1 UB website http biz LGservice com e mail http www LGEservice com techsup html December 2007 P NO 3350GDKM0020A Internal Use Only ...

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