Top part of screen greyed out

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • tech2014
    Badcaps Veteran
    • Aug 2014
    • 807
    • Canada

    #1

    Top part of screen greyed out

    I have a panasonic vierra 42" plasma tv that has the top half of the screen greyed out. Any ideas?
  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK

    #2
    Re: Top part of screen greyed out

    Can you supply a picture of the fault? It is hard to tell what you mean by "greyed out"...
    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

    • tech2014
      Badcaps Veteran
      • Aug 2014
      • 807
      • Canada

      #3
      Re: Top part of screen greyed out

      Here are the pictures of the tv.

      Click image for larger version

Name:	backtv.jpg
Views:	1
Size:	575.4 KB
ID:	1949458

      Click image for larger version

Name:	leftside2.jpg
Views:	1
Size:	462.5 KB
ID:	1949459

      Click image for larger version

Name:	screen.jpg
Views:	1
Size:	389.9 KB
ID:	1949460

      Click image for larger version

Name:	leftsideboard.jpg
Views:	1
Size:	567.0 KB
ID:	1949461

      The left side board is the Y SUS board I took out of the tv

      Comment

      • tom66
        EVs Rule
        • Apr 2011
        • 32560
        • UK

        #4
        Re: Top part of screen greyed out

        Probably Y-buffer fault. (SU or SD)
        Can you see Vscn test point on SC (Y-sustain) board?
        Please check the voltage and see what it is measuring. It should measure 120V to 150V wrt to -Vad (usually it is measured across a resistor.)
        Last edited by tom66; 08-24-2014, 04:44 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

        • tech2014
          Badcaps Veteran
          • Aug 2014
          • 807
          • Canada

          #5
          Re: Top part of screen greyed out

          I can smell something hot on the Y SUS board. The tv eventually shuts down after a few minutes on. I will get the voltages for you soon.

          Comment

          • tech2014
            Badcaps Veteran
            • Aug 2014
            • 807
            • Canada

            #6
            Re: Top part of screen greyed out

            I found another board, any idea what this does?

            Click image for larger version

Name:	back2.jpg
Views:	1
Size:	652.9 KB
ID:	1949464

            Comment

            • tech2014
              Badcaps Veteran
              • Aug 2014
              • 807
              • Canada

              #7
              Re: Top part of screen greyed out

              I found a load resistor damaged and looks like it has a burn mark on it. It also gets extremely hot and is the burning smell is from this part. Problem on Y SUS board or the SU board.

              It is on the left side board (Y-SUS)

              Click image for larger version

Name:	resistor.jpg
Views:	1
Size:	584.4 KB
ID:	1949466

              Comment

              • tech2014
                Badcaps Veteran
                • Aug 2014
                • 807
                • Canada

                #8
                Re: Top part of screen greyed out

                I get only 40 volts on Vscn. My Ve, VSUS are both good.

                Comment

                • tech2014
                  Badcaps Veteran
                  • Aug 2014
                  • 807
                  • Canada

                  #9
                  Re: Top part of screen greyed out

                  I FIXED THIS TV. It was an open circuit 0 ohm SMT resistor on the SU board. Fixed and tv now working YAY!!!!!!!!!!!

                  Comment

                  • mmartell
                    Badcaps Legend
                    • Oct 2013
                    • 3189
                    • Canada

                    #10
                    Re: Top part of screen greyed out

                    Nice job. How did you find the shorted component ?

                    Comment

                    • tech2014
                      Badcaps Veteran
                      • Aug 2014
                      • 807
                      • Canada

                      #11
                      Re: Top part of screen greyed out

                      Nothing shorted but the 0 ohm resistor measured OL in and out of circuit. This service manual for this tv actually had all the schematics which helped immensely.

                      Comment

                      • tom66
                        EVs Rule
                        • Apr 2011
                        • 32560
                        • UK

                        #12
                        Re: Top part of screen greyed out

                        Nice fix! Could you show us exactly what resistor for future reference? Or the component # on the schematic?
                        Yes, I do like that Panasonic provides full service guides for their plasmas - something for other manufacturers to look at doing. (I wish.)
                        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

                        Working...