Seiki SE42UMT, Standby Light, No power On

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  • TheDuDe06
    New Member
    • Aug 2020
    • 4
    • Canada

    #1

    Seiki SE42UMT, Standby Light, No power On

    Hi, I have a Seiki SE42UMT that don't power on anymore.

    The standby red LED will stay lit but nothing else.
    I can hear a constant high pitched sound from the power supply board.

    I already have replaced the power supply but the problem still persist so, we can rule out that the power supply board is good.

    I also inspected visually every boards and I can't see anything that could have burnt or blown capacitors.

    Here are attached few pictures of the 3 boards.

    Thank you !
    Attached Files
  • TheDuDe06
    New Member
    • Aug 2020
    • 4
    • Canada

    #2
    Re: Seiki SE42UMT, Standby Light, No power On

    Nobody have a hint where I need to look ?

    If I need to give more infos or more tests let me know !

    Thanks !

    Comment

    • neilc6
      Badcaps Legend
      • Nov 2015
      • 1550
      • Canada

      #3
      Re: Seiki SE42UMT, Standby Light, No power On

      If you have standby light and standby voltage and the TV doesn't turn on, the main board is suspect. Could be eeprom but don't see it in your pics. If you can find the eeprom, you can try freezing it within upside down can of duster before plugging in.

      Squealing can be caused by shorted caps on the main board. See if it stops when you unplug it and measure for shorts on the supply rails on the main.
      Last edited by neilc6; 06-26-2022, 07:16 PM.

      Comment

      • dskall
        Badcaps Legend
        • Oct 2016
        • 2905
        • usa

        #4
        Re: Seiki SE42UMT, Standby Light, No power On

        I would start unplugging things on the power board until high pitch sound stops and then narrow down which board is loading power supply.
        I assume no responsibility for any stupid suggestions I might post.

        Comment

        • TheDuDe06
          New Member
          • Aug 2020
          • 4
          • Canada

          #5
          Re: Seiki SE42UMT, Standby Light, No power On

          Thanks guys now I have something to work on. I'll let you know my results.

          Comment

          • nomoresonys
            Badcaps Legend
            • Jan 2013
            • 12097
            • U.S.

            #6
            Re: Seiki SE42UMT, Standby Light, No power On

            looks like the caps are not holding up, if I wanted to do the least, I would replace the what is it 4 1000 uf 25 volt caps, with 1000 uf 50 volt and see what happens, I suspect they were using cheap caps. hold up on the (I just got a new board) ALL the boards will be old, might not solve the problem but it's the simple place I would start at.
            Last edited by nomoresonys; 06-27-2022, 03:34 AM.

            Comment

            • nomoresonys
              Badcaps Legend
              • Jan 2013
              • 12097
              • U.S.

              #7
              Re: Seiki SE42UMT, Standby Light, No power On

              and check all the solder joints, they are prolly old too.

              Comment

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