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Sanyo DP50747 50" Plasma issues

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    #1

    Sanyo DP50747 50" Plasma issues

    First off, thank you to anyone and everyone who is able to help me out.

    I have recently been given a free (yay) 50" Sanyo DP50747 plasmatv that has a few issues, which I've been scouring to find information on, and I have made some slight headway on resolving the issues, though I am no where near done with this beast.

    First off, a list off things the tv does that seem abnormal.
    • Powers off a few times before staying on for irregular lengths of time
    • Image has what seemtobe called sparklies, of no particular color.I describe it more as a snowy looking image (not pixelated though)
    • The brightness or contrast seems like it is WAY too high, imageslooklike they have a solarized photo effect going on
    • There were some horizontal lines that went away after reconnecting the ribbon cables on what I believe are the Y driver boards


    What I have done so far
    • Checked voltages...
    • Lower voltagesfrom 3.3v to12v all appear within a stable and acceptable range (a variation of .1 vdc but steady)
    • Ve registers and adjusted to94.1 v, sticker inside says it should be 94v
    • Vs is adjusted to 207v, sticker states it should be 207
    • Va is at 63.2 sticker says it should be 63 but I couldn't get it much closer


    The image quality issues are occuring on all inputs, and adjusting the on screen brightness and contrast settings do virtually nothing to change the way the image looks.

    I've disconnected the Y-sus and the Z-sus boards and the power issue still occurs. I opted to pull the power supply board based on many problems being reported as caused by failed capacitors on this board, and after an extremely thurough inspection, I have found 3 capacitors that are barely bad.

    I guess my first hope isif someone can confirmthat the capacitors I have found are indeed bad, and if I am on the right track tosolving the issue.

    Pictures should be available here (sorry if it doesn't work, I'm still getting used to forums.
    http://sysmnky.imgur.com/
    Tags: None
    #2
    Re: Sanyo DP50747 50" Plasma issues

    If those caps are bulged they are bad, replace them.

    Comment

      #3
      Re: Sanyo DP50747 50" Plasma issues

      Thank you for the confirmation, wanted to be sure I was understanding correctly prior to making the trip to get replacements.I'll update with a bit more info once I get them replaced.

      Am Iunderstanding right that the bad capacitors could result in poor picture quality as wellas the power issue, or is it more likely that they are two different issues? Either way, I know it is a one step at a time process, mostly just curious.

      Comment

        #4
        Re: Sanyo DP50747 50" Plasma issues

        Going by that small snapshot, looks like it may be a samsung panel and boards.

        Samsung LJ44-00132A Power Supply Unit?

        PDP, S50HW-YD02? (or YB02)

        Same as used in these from the info at SJ website.

        SAMSUNG HPT5034X/XAA
        SAMSUNG HPT5044X/XAA
        SAMSUNG HPT5054X/XAA
        SAMSUNG HPT5064X/XAA
        SAMSUNG PPM50M7HBX/XAA
        SAMSUNG PS-50Q97HD
        SAMSUNG PS50Q96HDX/XEU

        I know in the Samsung model Q96 etc, That particular PSU was prone to dry joints on the heatsink mounted components and could cause random shutdowns.

        Yours looks specific to SANYO?

        Bulging caps is a no brainer but no harm in checking out the soldering and even reflowing any FETs or diodes mounting on the heatsinks.

        I had one set that would shutdown randomly and flex the board in the middle triggered a shut down, bad joints. Can't say if your PSU would suffer from this or not, just something to keep an eye out for as well.

        Also that panel suffers from shorted upper buffer boards and shorted/faulty ymain as well.

        If you go "advanced", "manage attachments" in the post, real easy to upload pics, max res 2000x2000.

        I would post a pic of the image issues to get the best comments from everyone.

        Comment

          #5
          Re: Sanyo DP50747 50" Plasma issues

          I'll try and get a couple pictures of whats going on that are decent quality. I've got the power supply board out and the capacitors removed, waiting until payday to get replacements and put them in.

          Also, I did try to get a video of what was going on. Uploaded it here http://youtu.be/T5NU_JOnh60

          If my understanding is correct,it is a Samsung panel (based on a big Samsung sticker inside the tv) and the power supply unit is indeed a Samsung LJ44-00132A. The set is branded as a Sanyo. When I get home I'll snap a couple pictures of the interior of the set and upload them as well.

          @tw2005 If I understand the way the Y Main and Y buffers work, then your statement about the buffers and Y Main being commonly shorted makes sense, as I have most of the horizontallines seen in the top half of the screen. Is there any way to test and repair the Y Main and Y Buffers,or is it more common to simply replace them should the issue continue after Ireplace the bad caps on the power supply unit?

          Thanks to everyone again for all the assistance.
          Attached Files

          Comment

            #6
            Re: Sanyo DP50747 50" Plasma issues

            I'm not too sure now looking at the video because the OSD looks ok ? only mentioned the buffer and y based on your description and because of the type of panel you had and it's a common problem.

            Does appear to be random noise through the whole display though.

            Comment

              #7
              Re: Sanyo DP50747 50" Plasma issues

              I think random noise would be a good description. It looked like there were pixels that retained the image that was being seen for a short time after I brought up the OSD. Sections of the blue stayed the color they were, and itlookedlike abunch of tiny bar graphs that were shrinking. Its definitely not easytodescribe, so sometime Monday night (probably late, once the kids are in bed) I'll be abletoreplace the bad capacitors, and assuming I haven't fried the power supply board or myself by then, I'll get better pictures and videos uploaded.

              Comment

                #8
                Re: Sanyo DP50747 50" Plasma issues

                Still no parts, local shop doen't have the correct sizes in stock, so I will not have any better pictures or video of what the issue looks like until I can get some ordered online. Are there any brands that are recommended when I do order them, or does it not make much of a difference? I had originally planned on getting whatever I could get locally, but since the internet offers a nearly limitless variety, I might as well get some that are reliable.

                Attached are a few pictures of the internals of the tv in the event that they become needed for further troubleshooting.
                Attached Files

                Comment

                  #9
                  Re: Sanyo DP50747 50" Plasma issues

                  Here is the service manual for this set.
                  Attached Files

                  Comment

                    #10
                    Re: Sanyo DP50747 50" Plasma issues

                    I worked on one of those power supplies in a Vizio 50" set. The Set would randomly shut down. I replaced the caps on the secondary side, but then it would not power on at all.
                    I resoldered all the components on that long heat sink (the second from the right) and all was well again.

                    Comment

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