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Samsung LN37A550P3Fxza increasingly aggravating

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    Samsung LN37A550P3Fxza increasingly aggravating

    I have done a lot of searching and have not hit on my symptoms. My unit powers up fine and without the cable box, or any input powered it goes into the "searching for signal" screen and stays on. Upon powering the cable box, the unit began to show a yellow/green snow and a harsh static was played through the speakers at what seemed full volume. This would last ten seconds or so, and I was unable to affect it with power, mute, input, or menu. The unit would then power off, recycle, and come on fine.
    This has gradually grown into a longer period of tries and recycles, where now it takes ten minutes of various screen statics and sometimes harsh sound, sometimes not. Finally, a weak picture of shadows, then maybe one more recycle and the unit works fine. I t will continue to work fine for the rest of the day. It seems like a "warm up" is needed for some component.
    I have taken the back off, gently cleaned all the dust off, inspected the boards, caps, connections, and solder, and everything looks good.

    I replaced the cable box with a new one Saturday. No change.
    I have read the basic troubleshooting stickys.
    AND the damn TV works fine after this start-up horror! (full volume static)

    #2
    Re: Samsung LN37A550P3Fxza increasingly aggravating

    Sounds like a main board issue to me. I'd be checking the caps on the main board with an oscilloscope for excessive ripple. As the caps get warm, the esr lowers.

    Comment


      #3
      Re: Samsung LN37A550P3Fxza increasingly aggravating

      http://s807.photobucket.com/user/bud...in=true&page=1
      Temporary solder 100uf 10V low ESR type in parallel with C102 which is on the bottom side of the main board, it is tricky soldering works but can be done, see what happen.
      I need to make a new thread for the 32, 37, and 46 LNA550P3 series I fixed last week with the same problem.
      BTW, caps on the power supply boards are OK, right?
      Attached Files
      Last edited by budm; 01-05-2015, 08:13 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


        #4
        Re: Samsung LN37A550P3Fxza increasingly aggravating

        Thank you for the replies. I have just begun to tackle this, will try to test caps on power board. They are visually OK. They are 6 yrs. old, average to low usage. The squealing and cycle on/off nails the symptoms. Thank you guys for guiding me in to the right parts. Warming the main board with a hair dryer seems to avoid the problem, for what that's worth.
        I don't think I'm capable of soldering on the main board, but now I have some good info to proceed with. You guys are great.

        Comment


          #5
          Re: Samsung LN37A550P3Fxza increasingly aggravating

          "Warming the main board with a hair dryer seems to avoid the problem, for what that's worth. " That was how I found out, narrowing it down was the problem.
          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


            #6
            Re: Samsung LN37A550P3Fxza increasingly aggravating

            Yes, poking around some other threads here I see that you have put your time in on this squealing issue. Many thanks.

            Comment

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