Samsung UN55HU6840 No picture has sound and backlights

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  • dskall
    Badcaps Legend
    • Oct 2016
    • 2905
    • usa

    #21
    Re: Samsung UN55HU6840 No picture has sound and backlights

    I assume no responsibility for any stupid suggestions I might post.

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    • dick_barton
      Badcaps Legend
      • Aug 2015
      • 6642
      • Wales

      #22
      Re: Samsung UN55HU6840 No picture has sound and backlights

      Thanks for the info.
      So it looks like the Tcon is a 3.3V Tcon. What voltage is on pin 4 when you switch on and when you bring it out of standby?
      Willing to help but I'm no expert.

      Comment

      • dskall
        Badcaps Legend
        • Oct 2016
        • 2905
        • usa

        #23
        Re: Samsung UN55HU6840 No picture has sound and backlights

        Don't see how 55" could run off 3.3v. Looks like maybe trace runs to ic2602? 2802. Also see a 13v panel on legend.
        I assume no responsibility for any stupid suggestions I might post.

        Comment

        • 2smoovedaddy
          Member
          • Aug 2012
          • 42
          • United States

          #24
          Re: Samsung UN55HU6840 No picture has sound and backlights

          Looks like 4485D maybe you can make it out. Had to magnify it to see it.
          Voltage on first 4 pins is 12.76 and 0 on the last 4.
          Sorry didn't see it had been posted already.
          Attached Files
          Last edited by 2smoovedaddy; 04-24-2017, 12:53 PM.

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          • dick_barton
            Badcaps Legend
            • Aug 2015
            • 6642
            • Wales

            #25
            Re: Samsung UN55HU6840 No picture has sound and backlights

            OK so it looks as though its a 12V supply to the Tcon. Can you measure the resistance from pins 5,6,7 or 8 to 0V (ground) with the set off and meter set to ohms.

            I suspect the chip is blown and is not switching the 12V input at pins 1,2 &3 to output pins 5,6,7 & 8 when Pin 4 goes to 12V
            Willing to help but I'm no expert.

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            • 2smoovedaddy
              Member
              • Aug 2012
              • 42
              • United States

              #26
              Re: Samsung UN55HU6840 No picture has sound and backlights

              All open(OL). By the way thanks for all you guys help.

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              • dick_barton
                Badcaps Legend
                • Aug 2015
                • 6642
                • Wales

                #27
                Re: Samsung UN55HU6840 No picture has sound and backlights

                If the resistance on the output pins 5,6,7, & 8 is high then it does not look like a short circuit causing the problem so I suspect the IC to be at fault.
                Willing to help but I'm no expert.

                Comment

                • dskall
                  Badcaps Legend
                  • Oct 2016
                  • 2905
                  • usa

                  #28
                  Re: Samsung UN55HU6840 No picture has sound and backlights

                  I would replace it their inexpensive. It's a 4435 P-Channel 30-V MOSFET SOP-8
                  Last edited by dskall; 04-24-2017, 04:39 PM.
                  I assume no responsibility for any stupid suggestions I might post.

                  Comment

                  • 2smoovedaddy
                    Member
                    • Aug 2012
                    • 42
                    • United States

                    #29
                    Re: Samsung UN55HU6840 No picture has sound and backlights

                    Will do I'll keep you posted on the results.

                    Comment

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