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

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3. Component doesn't display

Check J5004

Can you see the normal waveform?

Yes

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

Yes

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

No

No

J5004 may have problem. Replace this Jack.

After checking the input TR of component, you should decide to replace component switch or not.

After checking the Power of component 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 output 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 MST3361 you should decide to replace MST3361 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 General Guidance Do not use a line Isolation Transformer during this checkServicing Precautions IC Remove/Replacement Small-Signal Discrete Transistor Removal/ReplacementPower Output, Transistor Device Removal/Replacement Diode Removal/ReplacementGeneral SpecificationTV SpecificationApplication range Test method Chroma & Brightness WhiteComponent Video Input Y, CB/PB, CR/PR Mechanical specification RGB input PC/DTVAdjustment Instruction Application ObjectADC-Set Adjustment Set MethodPreparation for Adjustments & Setting of Device Required Test Equipment23LS7D-UB Hdmi 23LS7D-UB RGBAdjustment of White Balance Required EquipmentTroubleshooting TV/CATV doesnt displayVideo 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 TRANSISTORs & FETs ICsRESISTORs MNR04M0APJ680 68OHM 5% 1/16W 4P 8P R1185 R4007 0RJ1001C678 R4147 R6031 CONNECTORs SWITCHesCOILs & FILTERs & INDUCTORs JACKsOTHERs LED,DIP BL-BUBGE301 Round 3MMPage Page Mar