LG60PN5300 Not turning on

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  • doesntmind
    Senior Member
    • Feb 2014
    • 61
    • usa

    #1

    LG60PN5300 Not turning on

    Attempting to repair an LG60PN5300 that displays standby light yet does not turn on when pressing the power switch

    Standby readings:

    pin# - Desc - Standby
    1 - 17V - 17.2V
    2 - 17v - 17.2V
    3 - GND - 0V
    4 - GND - 0V
    5 - 5.2V - 5.3V
    6 - 5.2V - 5.3V
    7 - 5.2V - 5.3V
    8 - VS_DET - 2.8v
    9 - GND - 0V
    10 - GND - 0V
    11 - GND - 0V
    12 - VS_ON - .67V
    13 - 5.2V - 5.3V
    14 - 17V_DET - 2.36V
    15 - RL_ON - 1.25V
    16 - AC_ON - 5.2V
    17 - M_ON - .64V
    18 - AUTO_GND - 4.2V

    I tested the power switch and it appears to be fine

    The main board is missing an HDMI port which broke off, i dont see any shorts on the contacts left behind
  • doesntmind
    Senior Member
    • Feb 2014
    • 61
    • usa

    #2
    Re: LG60PN5300 Not turning on

    forgot to attach photos
    Attached Files

    Comment

    • doesntmind
      Senior Member
      • Feb 2014
      • 61
      • usa

      #3
      Re: LG60PN5300 Not turning on

      bump

      Comment

      • freakaftr8
        Badcaps Legend
        • Oct 2012
        • 3743
        • USA

        #4
        Re: LG60PN5300 Not turning on

        Sounds.like your mainboard has bricked. Have you tried jumpering 5v to ps_on? Also you can disconnect mainboard cable on this model I believe to have power supply rails come up.
        Did I leave the soldering iron on?

        Comment

        • R_J
          Badcaps Legend
          • Jun 2012
          • 9515
          • Canada

          #5
          Re: LG60PN5300 Not turning on

          Does the Vs or Va voltage come up for a second then drop off?
          Have you checked for shorted fets etc. on the y-sus and zsus boards, try disconnecting the cable going to the ysus and see if the Vs voltage comes up for a sec. on the power supply, if not try disconnecting the cable between the power supply & Zsus board and see if the Vs comes up fora second.
          You could also have a bad upper or lower buffer board.
          Check this thread https://www.badcaps.net/forum/showth...light=60PN5300 it might help
          Last edited by R_J; 12-20-2017, 12:36 PM.

          Comment

          • doesntmind
            Senior Member
            • Feb 2014
            • 61
            • usa

            #6
            Re: LG60PN5300 Not turning on

            Originally posted by R_J
            Does the Vs or Va voltage come up for a second then drop off?
            Have you checked for shorted fets etc. on the y-sus and zsus boards, try disconnecting the cable going to the ysus and see if the Vs voltage comes up for a sec. on the power supply, if not try disconnecting the cable between the power supply & Zsus board and see if the Vs comes up fora second.
            You could also have a bad upper or lower buffer board.
            Check this thread https://www.badcaps.net/forum/showth...light=60PN5300 it might help
            The Vs pins read a steady 206V on zsus and ysus boards.
            I've noticed the 15v pin on ysus was only reading 5v
            Attached Files

            Comment

            • R_J
              Badcaps Legend
              • Jun 2012
              • 9515
              • Canada

              #7
              Re: LG60PN5300 Not turning on

              Looks like the 15 volts could be produced on the Ysus board, buffer board could be loading the 15v down to 5v
              More info here https://www.badcaps.net/forum/showthread.php?t=45244
              I see heatsinks on the buffer ic's, do any of them get warmer then the others?, I believe you can run the tv with either the upper or lower buffers removed, (do this for testing and only a short period of time)
              disconnect the (upper) buffer board from the Ysus, also disconnect the ribbon connecting the upper & lower buffers, You can leave the buffers connected to the panel and don't need to disconnect them.
              Try the tv and see if you get a picture on the lower half of the screen. if you do, the upper buffer is bad.
              if not then unplug the tv, connect the upper buffer board back to the ysus and disconnect the the lower board and plug in and turn on the tv, see if there is a picture on the top half of the screen.
              Last edited by R_J; 12-20-2017, 08:53 PM.

              Comment

              • doesntmind
                Senior Member
                • Feb 2014
                • 61
                • usa

                #8
                Re: LG60PN5300 Not turning on

                Having the zsus board only connected to the power supply i still only read 5v on the 15v pin
                I believe 15V is produced by the zsus

                my reading on the connector that goes from main power supply to zsus reads
                1 - VS - 206V
                2 - VS - 206V
                3 - NC - 0V
                4 - GND - 0V
                5 - GND - 0V
                6 - VA - 55V
                7 - M5V - 5.25v
                Attached Files

                Comment

                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK

                  #9
                  Re: LG60PN5300 Not turning on

                  15V is most likely generated by Y board, actually... Using the yellow transformer onthe Y board.
                  If Vsc and -Vy are bad, then 15V may also be bad.
                  Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                  For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                  Comment

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