LG Plasma TV will not turn on - Need Help

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  • Meiko
    New Member
    • Jan 2014
    • 7
    • US
    #1

    LG Plasma TV will not turn on - Need Help

    Hello all. I'm in need of some help.

    I have a LG Plasma TV 50PC3DH that will not turn on. It died while watching a show when it blinked with a white screen two or three times before turning off. Now when I try to turn on the TV, it clicks like its trying but then, after about 3 seconds, it turns back off. No picture or light is shown while it's trying to turn on.

    I opened the TV and noticed some bulging capacitors on the power board, so I sent the power board to get repaired. When I reinstalled the power board, the symptoms didn't change.

    Next, I checked the resistance between the Vs and ground on the YSUS and the ZSUS boards and found a short on the ZSUS. I replaced the ZSUS board with a refurbished board. Still, the TV will not turn on.

    I checked all the voltages on the connectors, and they all seem to be correct. I don't know what to check next or how to find the problem component. If anyone can please give me some advice on how to determine what the problem is, I would greatly appreciate it.

    Attached is a visual of the tv circuitry.
    Attached Files

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    Tags: None
    • tds-1541
      Member
      • Jan 2014
      • 15
      • USA
      #2
      Re: LG Plasma TV will not turn on - Need Help

      This unit appears use the same chassis as a plasma that I was just able to repair: https://www.badcaps.net/forum/showthread.php?t=34861. Long story short, I had to replace a MOSFET on the power supply board as well as an defective Z-sustain board.

      The manual entitled " lg_50pc1dr_troubleshooting_manual.pdf" was VERY helpful. I would recommend that you download a copy of that. That PDF outlines resistance values for each board and their major components. You should quickly be able to determine which board/boards are bad by measuring the resistances and comparing them to the values in that PDF. Good luck!
      Last edited by tds-1541; 02-15-2014, 04:43 PM.

        Comment

        • Meiko
          New Member
          • Jan 2014
          • 7
          • US
          #3
          Re: LG Plasma TV will not turn on - Need Help

          Sorry for the slow reply, I had to go out of town.

          After going through the trouble shooting guide mentioned above, I checked what I could make sense of, but I did not come up with anything definitive. While checking all the voltages against what is printed on the ysus board again, I measured 5.8 volts on the +5VF pin on the connector from the ysus to the y driver board. All the other pins on the ysus board calling for 5 volts measure 4.9 volts. Does this show a faulty ysus board or is the 5.8 volts an acceptable reading?

          Also, how do I check to see if the y driver boards are ok?

          I'd really appreciate more help!

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