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Panny plasma TX-P42C3 won't turn on when warm

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    Panny plasma TX-P42C3 won't turn on when warm

    Dear 'mates,

    I'm in trouble with my Panasonic plasma TX-P42C3, hope you can help me.

    TV turns on and works perfectly as long as I turn it on when TV is cold, something like 1 hour or more after it was on last time.

    When I turn it on it will work fine for however long it is turned on, but if I turn it off after 20mins or more, when TV is warmed up, it won't turn on again, symptoms being as follows: green LED blinks for few seconds as it should when TV is turning on, then it stays lit like the TV is on, but nothing happens on screen, no sound. When I press any remote key, green LED blinks like it's receiving command, but when I depress that key LED turns off. Also, TV does not respond to keys on it's side, green led is not blinking when I'm pressing them. No blinking led error codes whatsoever!
    If I allow TV to cool for hour or so, It will turn on, everything is perfect, works like a charm.

    When TV works, no errors are displayed on self check screen, forcing factory settings does not help.
    In the old days this kind of fault would be considered as a cold joint issue, so i re-soldered whole power board (mpf6907) and logic board (TNPH0939), with soldering iron and hot air. No avail...

    I measured various voltages during normal operation and while TV is not operating (and should be). Differences on P6 connector are that 15Vc and 15Vs are not present in later case. Same goes for P_M_ON and S1. I checked all voltages on logic board that I could access (5V, 3.3V, 1.2V, 1.2V, 1.5V, 1.8V), everything is fine. Nothing is overheating anywhere on either board, be it while TV is operating properly, or while in fault state, and Peaks's heatsink is equally warm.

    Sorry for my bad english, if anything is unclear I'll try to clarify.
    Thanks for reading, hope you have some fresh ideas, 'cause I'm going slightly mad with this one...

    Best regards,
    Amdry

    #2
    Re: Panny plasma TX-P42C3 won't turn on when warm

    I'm thinking this is an A board issue. They can get hot and BGA solders can start to fail.

    Comment


      #3
      Re: Panny plasma TX-P42C3 won't turn on when warm

      Thank you for your answer!
      In service manual I saw that there is a "temp sensor", IC2001, should be 5-pin IC but I was unable to locate it on PCB. Do you think it's malfunction could explain what I'm seeing with this TV?

      Regards,
      Amdry

      Comment


        #4
        Re: Panny plasma TX-P42C3 won't turn on when warm

        Originally posted by Amdry View Post
        Thank you for your answer!
        In service manual I saw that there is a "temp sensor", IC2001, should be 5-pin IC but I was unable to locate it on PCB. Do you think it's malfunction could explain what I'm seeing with this TV?

        Regards,
        Amdry
        I doubt it,

        Comment


          #5
          Re: Panny plasma TX-P42C3 won't turn on when warm

          OK, then I'll burn IC8000 with hot air till it starts working properly or dies from heat, whatever happens first :-)
          I brought few laptop motherboards back to life doing so. Some of them worked for couple of months, but some lived for years 'till obsolescence.
          Wish me luck, will report back. Thanks!

          Regards,
          Amdry

          Comment


            #6
            Re: Panny plasma TX-P42C3 won't turn on when warm

            Here's what i would try:
            Grab a can of freezer spray,to cool down rapidly the A board,to start off with,if it isn't that,then you should be able to narrow it down to a individual component.A simple idea that should help greatly!.
            Good luck!

            Comment


              #7
              Re: Panny plasma TX-P42C3 won't turn on when warm

              Update: I reworked BGA chip and pretty much everything else on A board with hot air gun. TV worked perfectly for five days, and then all symptoms returned as nothing happened. So, new A board is required. Can you recommend where to buy it?
              Thanks for your assistance!

              Regards,
              Amdry

              Comment

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