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LG Plasma 60PK950 .. Powers on Sound ok

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    LG Plasma 60PK950 .. Powers on Sound ok

    Hi, have a 60PK950 LG Plasma here behaving for 4 years and then decided not to.

    Top/bottom screen flickers when powered on and after a few seconds both halves go almost blank with occaisional few flickering horiz lines once in a while but the sound is ok.
    If I press the input button, the system input menu sometimes appears and is visible but the top half flickers on/off and the bottom half flickers on/off at different rates and after a few seconds back to blank screen with some occaisional flickering thin horizontal lines.
    Control board led looks like its blinking.
    Powers on and after a while also goes to standby..I've tested Va/Vs and both are within range. I think power unit is behaving ok.

    I've tested Vz on the positive side of the resistor against frame as ground.. the voltage is inline with expected so I suspect ZSUS is ok.
    Testing Vy and Vsc on either side of the resistor against frame as ground finds no voltage.

    Questions:
    1)Is this a bad YSUS you think?
    2)Am I testing the Vy/Vsc/Vz resistors correctly by using frame as ground? I do not see any onboard grounds..
    3)Since I do see the input screen for a few seconds before it goes blank on each powerup, doesnt that mean both Y buffers are ok or could they be struggling or is it all the YSUS?
    I assume if the buffers were bad they wouldnt even give a few seconds..
    4)I see fuses on these boards..but I'm used to the old fashion glass fuses with the wire inside.. if one of these new non-glass fuses blows how can you tell? Are these new fuses resettable or something?


    Regards,
    Eins

    #2
    Re: LG Plasma 60PK950 .. Powers on Sound ok

    A couple of pics of the boards inside the set will help identify the chassis model and jog memories as to what fails.....
    TELEFIX

    How PLASMA SCREENS WORK, X-SUS and Y-SUS what they do--
    http://www.irf.com/technical-info/appnotes/an-1088.pdf
    PLEASE DO NOT EMAIL ME PRIVATELY FOR REPAIR ADVICE. QUESTIONS BELONG ON THE FORUM!

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      #3
      Re: LG Plasma 60PK950 .. Powers on Sound ok

      I'll have to get my borrowed camera back and take some pics later but an inspection shows no blown caps. Its a fairly standard layout of LG plasma tvs from what I see on the internet. YSUS on the left connected to the buffers on the edge, power board in the center and ZSUS on the right.
      Any ideas based on the symptoms and voltages checked and my list of questions in general above?
      Thanks

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