LG Electronics 20LS7D(C)-UB service manual Rgbpc doesnt display

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4. RGB_PC doesn't display

Check input connect P7004.

Can you see the normal waveform?

Yes

Check the input of Component switch(IC5001). Can you see the normal waveform?

Yes

No

No

P7004 may have problem. Replace this Jack.

After checking the input TR of RGBHV, you should decide to replace these components or

not.

Check the output of Component switch(IC5001). Can you see the normal waveform?

Yes

Check the input of MST3361(IC7012, Pin 6,9,12). Can you see the normal waveform?

Yes

No

No

After checking the Power of RGB switch you should decide to replace component switch or not.

After checking the Power of MST3382M you should decide to replace MST3382M or not.

Check the input of MST3361(IC7012). Can you see the normal waveform?

Yes

Check the input and output of BCM3550(IC1001). Especially you should check

The H,V sync and clock.

Can you see the normal waveform?

No

Yes

After checking the Power of MST3382M you should decide to replace MST3382M or not.

This board has big problem because Main chip(BCM3550) have some troubles. After checking thoroughly all path once again, You should decide to replace BCM3550 or not.

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Contents LCD TV Contents Do not use a line Isolation Transformer during this check General GuidanceServicing Precautions Small-Signal Discrete Transistor Removal/Replacement IC Remove/ReplacementPower Output, Transistor Device Removal/Replacement Diode Removal/ReplacementApplication range Test method SpecificationGeneral SpecificationTV White Chroma & BrightnessComponent Video Input Y, CB/PB, CR/PR RGB input PC/DTV Mechanical specificationApplication Object Adjustment InstructionSet Method ADC-Set AdjustmentRequired Test Equipment Preparation for Adjustments & Setting of Device23LS7D-UB Hdmi 23LS7D-UB RGBRequired Equipment Adjustment of White BalanceTV/CATV doesnt display TroubleshootingVideo doesnt display Component doesnt display Rgbpc doesnt display Hdmi doesnt display LCD Exploded View Exploded View Parts List Replacement Parts List Description / Specification C1608C0G1H220JT 22pF 5% 50V C0G -55TO+125C DIODEs RESISTORs ICsTRANSISTORs & FETs MNR04M0APJ680 68OHM 5% 1/16W 4P 8P R1185 R4007 0RJ1001C678 R4147 R6031 SWITCHes CONNECTORsCOILs & FILTERs & INDUCTORs JACKsLED,DIP BL-BUBGE301 Round 3MM OTHERsPage Page Mar