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Visio VP50 HDTV20A Bad Picture No Sound

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    #1

    Visio VP50 HDTV20A Bad Picture No Sound

    So I obtained this 50" from a friend that would not power on. I removed the back cover and checked all the fuses first. FL81 on the P/S board was blown. I replaced that fuse and the TV powered on. Here is the issue, I have no sound and the picture is really bad. See the pic below. I have looked over the P/S board, Y board, X board as well as the buffer boards for any burnt components or leaky caps. All the boards look good as well as the fuses. The only other thing that is a bit bizarre to me is that when I measure the voltage on both sides of the FL81 fuse that I replaced, I only get about .93 VAC on both sides. The FL80 fuse to the right of FL81 has 120VAC on both sides.

    Any suggestions?

    Tags: None
    #2
    Re: Visio VP50 HDTV20A Bad Picture No Sound

    You have a Z-sustain issue. A bad Z-sustain causes a fill-in effect and a dim picture, sometimes with a purple/lilac tint. The Z-sustain is on the right hand side of the TV, when looking from the back.

    The fuses are probably double pole so one for live and one for neutral, if you are measuring relative to case earth. Therefore it is expected that you have different voltages on each.
    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

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      #3
      Re: Visio VP50 HDTV20A Bad Picture No Sound

      Thanks for the reply. Yes you are correct about the fusees, didn't take that in to consideration. Your reference to the Z-sustain board, I assume that is the same as the X-Main board. I pulled the board off and all appears to be good from what I have checked on it. What usually goes bad with these boards? It seems to be a fairly simple piece of electronics. Mostly Mosfet and Rectifiers. All the caps, diodes and resistors are good.

      Not sure why this board would have anything to do with the no sound issue. Is it possible for the main board to be defective and cause the no sound and fill in effect pic?

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        #4
        Re: Visio VP50 HDTV20A Bad Picture No Sound

        Originally posted by rtsphotography View Post
        It seems to be a fairly simple piece of electronics. Mostly Mosfet and Rectifiers. All the caps, diodes and resistors are good.
        I wish. Debugging sustain boards is not easy. Driving a plasma panel requires a precise sequence of things to happen. For example, for the Y-sustain board, a sequence of events might be: A pre-charge event happens for each line which makes the cells change faster (but makes the screen glow, so black levels aren't as good.) Then the display data needs to be "written" to the screen with a high voltage (~400V) pulse, for each subpixel in the current line and subframe. Then, it needs to be "sustained", i.e. made to display, with an alternating +/-200V waveform (typically 5-20 cycles, in combination with the Z-sustain.) Then, an erase pulse is applied, around -190V, to clear the memory each pixel has. This must be done for every single line on the screen and this happens at least 400 times a second for 8-bit colour, so that's 307,200 lines per second... and pulses on the order of several megahertz. In addition, there's a section called the energy recovery driver, which can steal excess energy from the display (which would normally be wasted on every subframe), typically dropping power consumption by up to 200W. (Despite the fact that this circuit costs extra to include, and *most* manufacturers don't care about energy savings, substantial savings are made on the power supply components because of this.)

        When the Z-sustain goes bad the alternating voltage doesn't appear on one side of the screen so it doesn't discharge properly. Also, the writing and erasing doesn't seem to work properly (causing the fill-in effect), but I don't fully understand why not. All I know is... that it does it! I've tried it, unplugging the Z-sustain on an LG plasma of mine made the fill-in effect appear and it also made the picture kind of purple-tinted.

        HOWEVER, the majority of failures are short circuit, which blows the fuse on the sustain boards... but it usually leaves the mains fuse untouched.

        I'm not sure if you have a Samsung or LG. It's X-main for Samsung but this board does the same as Z-sustain.

        Originally posted by rtsphotography View Post
        Not sure why this board would have anything to do with the no sound issue. Is it possible for the main board to be defective and cause the no sound and fill in effect pic?
        Most likely you have TV speakers turned off in the menu. Was the same for an LG I have. Or the on-board amplifier is dead, but that's quite rare.
        Last edited by tom66; 02-26-2012, 09:13 PM.
        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

        Comment

          #5
          Re: Update - Working! Visio VP50 HDTV20A Bad Picture No Sound

          Originally posted by tom66 View Post
          I'm not sure if you have a Samsung or LG. It's X-main for Samsung but this board does the same as Z-sustain.
          It is a Samsung Panel

          Originally posted by tom66 View Post
          Most likely you have TV speakers turned off in the menu. Was the same for an LG I have. Or the on-board amplifier is dead, but that's quite rare.
          Speakers were on, was able to make it out in the menu even with the bad display.

          However:
          Some bizarre events have happened. All I did was put the X-Main back in plugged everything in and wallah it WORKS!!!! Sound and Picture!!! Ive been playing a movie on it for about 45 minutes now. One small issue remains, I have a thin black line on the upper part of the display as you can see in the picture below.

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            #6
            Re: Update - Working! Visio VP50 HDTV20A Bad Picture No Sound

            Originally posted by rtsphotography View Post
            One small issue remains, I have a thin black line on the upper part of the display as you can see in the picture below.
            Looks like I have found the issue related to the black line. The upper Y-Buffer FFC looks like it has been damaged or possibly melted. I took a good look and it appears to have 3 lines on the FFC damages and exactly 3 lines on the panel are black. I have thought about attempting to repair the breaks on the FFC. Whats your guys take on that.

            Here is a pic of the FFC.

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              #7
              Re: Update - Working! Visio VP50 HDTV20A Bad Picture No Sound

              Originally posted by rtsphotography View Post
              Looks like I have found the issue related to the black line. The upper Y-Buffer FFC looks like it has been damaged or possibly melted. I took a good look and it appears to have 3 lines on the FFC damages and exactly 3 lines on the panel are black. I have thought about attempting to repair the breaks on the FFC. Whats your guys take on that.

              Here is a pic of the FFC.

              Sadly, it's unrepairable. The FFCs are bonded to the screen. It could have been broken by a screwdriver or sharp implement when disassembling it. You could give it a go, but someone else here (graham01) had a similar problem with an LCD and he couldn't repair it.
              Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
              For service manual, schematic, boardview (board view), datasheet, cad - use our search.

              Comment

                #8
                Re: Visio VP50 HDTV20A Bad Picture No Sound

                What is the panel model? I have a 50 inch Samsung panel that may work for you. Mine is a S50HW-YB01. Let me know if you are interested!

                Comment

                  #9
                  Re: Visio VP50 HDTV20A Bad Picture No Sound

                  Originally posted by rpgruss View Post
                  What is the panel model? I have a 50 inch Samsung panel that may work for you. Mine is a S50HW-YB01. Let me know if you are interested!
                  I looked and my panel is Model # S50HW-YD02 manufactured Nov 4, 2007. I wonder if they are interchangeable? How much you asking for the panel if they are?

                  Comment

                    #10
                    Re: Visio VP50 HDTV20A Bad Picture No Sound

                    I highly doubt they are compatible, but if you want it I'll sell it for $50, which is how much I bought the TV for. Shipping's gonna be super expensive though if you are in Washington state though :/

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                      #11
                      Re: Visio VP50 HDTV20A Bad Picture No Sound

                      The ribbon is fixable, you just have to get creative and be really really careful. Can you get something under the ribbon? If you can get a strip of plastic or thin cardboard under it, you can attempt to glue the ribbon to it on the underside so it won't move (use slow drying glue otherwise there won't be enough time to wedge the strip of plastic inside before the glue dries), then once the glue sets, carefully scrape off some of the plastic in the ribbon to expose the conductor on both sides, then bridge the gaps with conductive ink.
                      Originally posted by PeteS in CA
                      Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                      A working TV? How boring!

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                        #12
                        Re: Visio VP50 HDTV20A Bad Picture No Sound

                        Originally posted by rtsphotography View Post
                        I looked and my panel is Model # S50HW-YD02 manufactured Nov 4, 2007. I wonder if they are interchangeable? How much you asking for the panel if they are?
                        I did some check and it looks the S50HW-YB01 is not compatible. Appreciate the offer. I'm gonna try to fix the ffc, thankfully I have excellent eye sight cause them traces are tiny.

                        Comment

                          #13
                          Re: Visio VP50 HDTV20A Bad Picture No Sound

                          I have a S50HW-YD02 and it is giving me a error code A12 UVP. I replaced a burnt fuse at the F5702 on board #TB399AA47. I also replaced a capacitor I thought was bulging on the main board, but still give the same error code.There is no picture or noise. It made a clicking noise when first turn on. Thanks.

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