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Samsung PS51d6900 not so well

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    Samsung PS51d6900 not so well

    I have always liked this set and the picture has been great. However, a couple of weeks back (during the football ) we had a small power cut, a few seconds at best. The TV turned off and on and was fine. For the next few days it turned itself off and on a couple of times until eventually it turned off and stayed that way with just sound coming back briefly for around a minute. When unplugged at the mains and re connected it turned on but no standby light, the led just flashed 5 or six times so something was on but no picture.

    The result is I now have a 55 inch lg (not oled) which is nice but I do not think the tv is as good for films so I want to fix my plasma.

    I removed the back panel and noticed that the green led on the logic board was not flashing at all, not even lighting. I tested a few voltages as per threads here but was not getting the readings expected. I bought a replacement logic board, I now have standby, the set turns on and off with the remote and the green light flashes every second. However still no form of screen activity.

    I have the set in a separate room now with no input source which does not help but I expected to be able to see something on the screen, even the Samsung test screens do not show when I short the logic board clips as per their video.

    I have taken readings and some appear very wrong.

    They are as follows,

    In standby I have a 5.2v reading on the standby plug
    PS on also has 3.28v so all good there.


    When I check PS on at switch on it goes from 3.28 to 168v, according to the Sammy video this is wrong and should be 0?

    VS on at turn on give 3.29v so that is fine.

    VA should be 58 and reads 58
    VSC should be -187 and reads -186.2
    VS shold be 207 and reads 207

    BUT VE should be 80 and reads 191.3. How did this happen?

    So as far as I can see I have two incorrect readings and thought it was best to get help at this time before going any further.

    This is a view of the set as it stands. I cannot see any problem capacitors or problem areas.



    "y" side



    "X" and main.



    Power supply


    #2
    Re: Samsung PS51d6900 not so well

    Check here first https://www.badcaps.net/forum/search...archid=6827103

    Comment


      #3
      Re: Samsung PS51d6900 not so well

      Originally posted by sordids999 View Post
      Hi,

      Thank you for responding, I had done that search and also read the plasma repair tips thread but seem to be going in circles now.

      I hoped to get an idea of what approach to take with the tests and results I had posted because they are not meaning too much to me just now. In time they may but I do not want to damage the set switching it on and off without a real steer.

      Comment


        #4
        Re: Samsung PS51d6900 not so well

        have you tried running test patterns ?
        have you tested the buffer board ?

        Comment


          #5
          Re: Samsung PS51d6900 not so well

          Yes,

          Tried the test pattern if that is connecting the two upper pins on the logic board, nothing showed. I have run the meter over the y buffer connections whilst in place but probably not ideal, I could disconnect the ribbons again and remove the board completely. It was those voltage readings that made me hold up a little.
          I probably should test the buffer. I will do it and post the result later. There is a copper ground spot on the board, I take it that is where the meter probe sits while I run it over the pins?

          Comment


            #6
            Re: Samsung PS51d6900 not so well

            Originally posted by dave247 View Post
            Yes,

            Tried the test pattern if that is connecting the two upper pins on the logic board, nothing showed.
            Had you removed the LVDS cable to the Logic board when you carried out the test?
            Willing to help but I'm no expert.

            Comment


              #7
              Re: Samsung PS51d6900 not so well

              Originally posted by dick_barton View Post
              Had you removed the LVDS cable to the Logic board when you carried out the test?
              Yes, I followed the Samsung video on youtube, just tried it again after testing y buffer, nothing. Powers on, green light flashes.

              Buffers seem ok, I used one of the pins on the block which triggered a noise on the meter when the other pin was on ground


              Still getting192v on VE but the sticker says 80? Maybe should just get an X sus board

              Comment

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