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NEC PX-61m1a Horizontal split w/pixeled color

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    #1

    NEC PX-61m1a Horizontal split w/pixeled color

    Hi guys, I have been doing some reading about my issue. I am thinking its the y-sus board on my TV that has gone bad. I would love to fix it on the board level if possible. I have a complete parts TV for swapping boards.
    The problem:
    The screen is split in half horizontaly. On the bottom of each half the picture is grainy and pixelated. The upper portions of each half look pretty good. I tried taking pictures but every picture I took wouldn't capture the issue..
    History:
    About a year ago I got the old girl and only the lower 1/3 or so had a picture, the rest was black. I do some research and it seemed to point at a buffer. I picked up another buffer board...but no go. I was lucky to find a thread somewhere where the person said to replace 2 caps on the main board. He had the exact issue I had. I removed them, tested them(with just a DMM) and they tested good. I replaced them anyway. Shazaam it worked well for a year!! I left the new buffer board in there. I never adjusted any voltages however.
    I know enough to be dangerous but thats about it...
    If someone has some ideas that would be great!
    Thanks very much!
    Tags: None
    #2
    Re: NEC PX-61m1a Horizontal split w/pixeled color

    I would consider the digital board. Clean and reseat any connectors going to this board. The digital board generates the control signals for the X-Drive and Y-Drive boards for the plasma panel, as well as loading the data into the Data Drivers and controlling the buffer board timing.
    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

      #3
      Re: NEC PX-61m1a Horizontal split w/pixeled color

      Thanks so much, I will get back with results!

      Comment

        #4
        Re: NEC PX-61m1a Horizontal split w/pixeled color

        OK, Results not so good...
        Cleaned up a bunch of ribbon cables and worked some connectors
        Now there are large blocks accross the top and the bottom. RED... its all red .
        Seriously, its all red ,there is an image kinda. IThat line still is there although with all the solid red its haaardly noticableI also noticed what seems like a transformer on the power supply that is hotter than the rest and singing.
        Yep, kids were glad dad tried to fix the TV...

        Comment

          #5
          Re: NEC PX-61m1a Horizontal split w/pixeled color

          You probably didn't seat one of the cables properly on the digital board, I have had this occur before when I did not do so.
          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

            #6
            Re: NEC PX-61m1a Horizontal split w/pixeled color

            Boy, you are fast. I did consider that , so I tried to look for one that may be a squew. I will definately look again.
            What do you think about the hot singing transformer? There are 2 or 3in a vertical line. Its the top one thats hot(I know that wont mean much but I thought I would be specific).
            Also, thanks for your help and time!

            Comment

              #7
              Re: NEC PX-61m1a Horizontal split w/pixeled color

              If the panel is full red, it will be using a lot of power (especially for 61", perhaps up to 700W) hence it will sing (high current and high frequency causing audible noise.) If the panel were darker, it would probably not sing.
              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: NEC PX-61m1a Horizontal split w/pixeled color

                OK, so I played with it quite a bit. Found out the red screen was self inflicted. It was one of those small connectors with 20-25 pins in a little over an inch. Yep might a been a little rough with that one . Straightened the pin and soldered it back to the board.
                So, with the red gone I then changed the board that feeds the y-sys. Still the same. I then put in the y-sus and buffers( all from the other TV). Same picture.
                I was watching the TV after 15 min or so and the whole top half went black....So back my y-sus and buffers went!
                The Power supply xfmer was still singing the whole time, so I replaced that. Then I found out why the other TV broke. So Back my Power supply went.
                I then changed the board where the inputs go in and the board it feeds.. still the same!!! Now I am getting frustrated...

                Comment

                  #9
                  Re: NEC PX-61m1a Horizontal split w/pixeled color

                  The xfmer that sings is constantly changing pitch with the picture. I checked 3 voltages on it and they are spot on. 170 70 and 5 VDC...

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