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LG42 PDP 42x3 No Relay/Audio/Video

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    LG42 PDP 42x3 No Relay/Audio/Video

    Hi all, I've got a 2006 Polaroid PLA4248, that will prime up, but nothing more. It wont relay on or off... simply stays primed.

    It initially failed the video only, then audio as well after turning on and off a few times.
    The set is quiet when on, no buzz. Though causes great signal interference with an AM boom box plugged into the same wall circuit.
    I've had it since new, no abuse or trauma to it. In 2006, they didn't come with cooling fans.

    The On/Off LED acts normally, red when off, blue when on. No green that I have ever seen since new. I've been studying for weeks the service manuals: LGE PDP 2K6 .... PDP42X3*, and PLA-4248.

    No other buttons are usable.... No Menu access from the Menu button or remote. I have not read any way to manually switch into test mode or menu mode.
    The Vacuum exhaust nipple appears intact. All fuses check out,
    and Y and Z boards show proper voltage through their fuses.

    I have inspected under magnification, all caps on all boards, and find no abnormalities, no bulging, cracks, leakage, no smell. I have confirmed all power supply board output voltages to be as specified on the attached label.... with the exception of the high voltage being 187.5 when 186 is specified.
    I have found these same measurements when the TV is "On" with primed display, as well as when all cables are disconnected from the Power Supply board... sans the main.

    The upper three of the four heat indicator LEDs light up on the controller board.

    I have not applied a jumper to the Auto Mode/ Normal switch on the Power Supply board because I find on instructions expounding on doing so.
    The red LED on the Power Supply remains off when the TV is on with primed display.

    The red LED on the 667-PH42FB6-20 Power Supply board will light steadily...... if the rainbow colored cable from X603 of the P/S board remains connected to the 782-PHIFB6-690A Digital Processing Board, aka, Data Processing Board... all other cables disconnected to the P/S.

    Once the P/S board is in protected mode (LED ON), the voltages mentioned before become null. So this seems good.

    The red LED remains off when all cables are disconnected from the Power Supply board...sans the main.

    I have yet to inspect the back side of any boards, and will likely swap in a new Data Processing Board though would be grateful for the input of others.
    Thanks, Sixstrung

    #2
    Re: LG42 PDP 42x3 No Relay/Audio/Video

    i would look at other voltages on the processor too.
    seems these things were built with cheap caps that would blow guts out the bottom and short.seen these near linear regs and shorted when they go.

    Comment


      #3
      Re: LG42 PDP 42x3 No Relay/Audio/Video

      Originally posted by sixstringr View Post
      Hi all, I've got a 2006 Polaroid PLA4248, that will prime up, but nothing more. It wont relay on or off... simply stays primed.

      It initially failed the video only, then audio as well after turning on and off a few times.
      The set is quiet when on, no buzz. Though causes great signal interference with an AM boom box plugged into the same wall circuit.
      I've had it since new, no abuse or trauma to it. In 2006, they didn't come with cooling fans.

      The On/Off LED acts normally, red when off, blue when on. No green that I have ever seen since new. I've been studying for weeks the service manuals: LGE PDP 2K6 .... PDP42X3*, and PLA-4248.

      No other buttons are usable.... No Menu access from the Menu button or remote. I have not read any way to manually switch into test mode or menu mode.
      The Vacuum exhaust nipple appears intact. All fuses check out,
      and Y and Z boards show proper voltage through their fuses.

      I have inspected under magnification, all caps on all boards, and find no abnormalities, no bulging, cracks, leakage, no smell. I have confirmed all power supply board output voltages to be as specified on the attached label.... with the exception of the high voltage being 187.5 when 186 is specified.
      I have found these same measurements when the TV is "On" with primed display, as well as when all cables are disconnected from the Power Supply board... sans the main.

      The upper three of the four heat indicator LEDs light up on the controller board.

      I have not applied a jumper to the Auto Mode/ Normal switch on the Power Supply board because I find on instructions expounding on doing so.
      The red LED on the Power Supply remains off when the TV is on with primed display.

      The red LED on the 667-PH42FB6-20 Power Supply board will light steadily...... if the rainbow colored cable from X603 of the P/S board remains connected to the 782-PHIFB6-690A Digital Processing Board, aka, Data Processing Board... all other cables disconnected to the P/S.

      Once the P/S board is in protected mode (LED ON), the voltages mentioned before become null. So this seems good.

      The red LED remains off when all cables are disconnected from the Power Supply board...sans the main.

      I have yet to inspect the back side of any boards, and will likely swap in a new Data Processing Board though would be grateful for the input of others.
      Thanks, Sixstrung
      The symptoms indicate a failure of the Digital Signal board (AKA Main board or Small Signal Board) rather than the plasma panel and it's support boards.

      That board was built by LG, and is used by a number of LG TVs, including the 42PC3D series. The service manual for the LG 42PC3D series has schematics. I would pay particular attention to the voltage regulators and caps on that board.

      I would not that there is a board available on eBay for about $50 delivered. I'm not sure I trust the source.

      PlainBill
      For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

      Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

      Comment

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