Philips 47pfl8404h/12 no power on

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  • Nawual
    Senior Member
    • Jul 2016
    • 65
    • Spain

    #1

    Philips 47pfl8404h/12 no power on

    Hello,I have this TV that does not turn on, only the blue LED flashes. I have measured the voltages that come out of the PSU and I have 3.5 in power-on and 3.3v in VSB, you can see it in the photo.But in the others only 0v.
  • Nawual
    Senior Member
    • Jul 2016
    • 65
    • Spain

    #2
    Re: Philips 47pfl8404h/12 no power on

    I have removed the PSU from the TV, and I have connected PS-ON with the last 3.3v pin through a 1M resistor and I still have no tension on the 12 and 24v pins.

    Comment

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #3
      Re: Philips 47pfl8404h/12 no power on

      Can we see the pictures of the whole top view and bottom view?
      We also need the pictures of the whole back side of the TV showing all boards so we can see how they are connected together.
      The resistor should be between 470 ~ 1000 Ohms range, 1M is way too high for it,
      Last edited by budm; 04-20-2018, 01:54 PM.
      Never stop learning
      Basic LCD TV and Monitor troubleshooting guides.
      http://www.badcaps.net/forum/showthr...956#post305956

      Voltage Regulator (LDO) testing:
      http://www.badcaps.net/forum/showthr...999#post300999

      Inverter testing using old CFL:
      http://www.badcaps.net/forum/showthr...er+testing+cfl

      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
      http://s807.photobucket.com/user/budm/library/

      TV Factory reset codes listing:
      http://www.badcaps.net/forum/showthread.php?t=24809

      Comment

      • Nawual
        Senior Member
        • Jul 2016
        • 65
        • Spain

        #4
        Re: Philips 47pfl8404h/12 no power on

        Hi Budm,sorry, the resistor is 1000oh.
        I have found the scheme of this PSU and I have realized that the transistors that go to the 3.3v are PNP, then it is inverse. So I have joined the PS-ON pin with the SGND1 that is next to it. And I have measured the 12v and 24v pins and bingo!, I have all the tensions. Now I have to find out why the PSU is not activated.

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #5
          Re: Philips 47pfl8404h/12 no power on

          So it is active LOW for the PS-ON, I should have caught that when I look at you picture in post one with 3.5VDC is already present without the resistor.
          At this point the main board is not pulling the PS-ON line to low, so next place to check will be the main board.
          Can you please also upload the diagram of the power supply so it will help other people in the future?
          Never stop learning
          Basic LCD TV and Monitor troubleshooting guides.
          http://www.badcaps.net/forum/showthr...956#post305956

          Voltage Regulator (LDO) testing:
          http://www.badcaps.net/forum/showthr...999#post300999

          Inverter testing using old CFL:
          http://www.badcaps.net/forum/showthr...er+testing+cfl

          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
          http://s807.photobucket.com/user/budm/library/

          TV Factory reset codes listing:
          http://www.badcaps.net/forum/showthread.php?t=24809

          Comment

          • Nawual
            Senior Member
            • Jul 2016
            • 65
            • Spain

            #6
            Re: Philips 47pfl8404h/12 no power on

            Yes, it was stupid to put up the resistance since there were 3.3v. I go up the diagram for those who may need it. I will continue with the motherboard, I'll tell you.
            Attached Files

            Comment

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