vp50hdtv10a Buffer testing

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  • topfli8979
    Badcaps Veteran
    • Oct 2012
    • 311
    • USA

    #1

    vp50hdtv10a Buffer testing

    I have a Vizio p50hdtv10a, what is the proper way to test the ic's on the buffer boards? I have put meter in diode mode, grounded on buffer board then ran all through the pins connecting to the panel. I have gone through 2- y sustains, it works for about a hour then starts flashing screen. So its gotta be the buffers shorting out the y boards.
  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK

    #2
    Re: vp50hdtv10a Buffer testing

    Samsung panel? In which case it's unlikely to be the buffers but the power supply going crazy. We are seeing another TV with same symptoms. Nominally 200V output measuring more than 300V! This probably kills the Y-main in short time.
    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

    • topfli8979
      Badcaps Veteran
      • Oct 2012
      • 311
      • USA

      #3
      Re: vp50hdtv10a Buffer testing

      Its a LG panel, voltages are all good. I even thought of the power supply also, replaced with different power board after first y board went. Did the same thing after about a hour. Its destroying the Ipms some how.

      Comment

      • tom66
        EVs Rule
        • Apr 2011
        • 32560
        • UK

        #4
        Re: vp50hdtv10a Buffer testing

        Check the Vs to be sure. It's pretty rare for IPMs to die from failed buffers on an LG.
        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

        • topfli8979
          Badcaps Veteran
          • Oct 2012
          • 311
          • USA

          #5
          Re: vp50hdtv10a Buffer testing

          195.7 vs. Steady. 60 va. Steady

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #6
            Re: vp50hdtv10a Buffer testing

            Hmm, what about the -Vy and Vsc?
            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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            • topfli8979
              Badcaps Veteran
              • Oct 2012
              • 311
              • USA

              #7
              Re: vp50hdtv10a Buffer testing

              199 vsc, 114 -vy

              Comment

              • tom66
                EVs Rule
                • Apr 2011
                • 32560
                • UK

                #8
                Re: vp50hdtv10a Buffer testing

                -Vy looks too low to me. Should be close to -200V. Can you post a picture of the plasma panel voltage sticker?
                Also, you need to check Vs when the screen is flickering.
                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

                • topfli8979
                  Badcaps Veteran
                  • Oct 2012
                  • 311
                  • USA

                  #9
                  Re: vp50hdtv10a Buffer testing

                  All of these readings are with a good Y main installed, sorry I didnt tell you that, Im just trying to get this figured out so I dont blow another. Only running the set for a few seconds at a time to test. I will get the picture of the voltage sticker.

                  Comment

                  • topfli8979
                    Badcaps Veteran
                    • Oct 2012
                    • 311
                    • USA

                    #10
                    Re: vp50hdtv10a Buffer testing

                    sorry for poor picture quality.
                    Attached Files

                    Comment

                    • drpj23
                      Badcaps Veteran
                      • May 2012
                      • 528
                      • USA

                      #11
                      Re: vp50hdtv10a Buffer testing

                      I think the readings just got flipped....but if 114 is vsc then that also is a little low..but not enough to affect anything.

                      Comment

                      • topfli8979
                        Badcaps Veteran
                        • Oct 2012
                        • 311
                        • USA

                        #12
                        Re: vp50hdtv10a Buffer testing

                        drp, you are right the -vy is -199, the vsc is 114. Wouldn't I need a scope to adjust the vsc?

                        Comment

                        • tom66
                          EVs Rule
                          • Apr 2011
                          • 32560
                          • UK

                          #13
                          Re: vp50hdtv10a Buffer testing

                          I think you need to get -Vy first. -Vy is important for erasing the display, pixels will get stuck on without correct -Vy.
                          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

                          • topfli8979
                            Badcaps Veteran
                            • Oct 2012
                            • 311
                            • USA

                            #14
                            Re: vp50hdtv10a Buffer testing

                            I can do this with a vmeter, just adjusting the -vy pot?

                            Comment

                            • tom66
                              EVs Rule
                              • Apr 2011
                              • 32560
                              • UK

                              #15
                              Re: vp50hdtv10a Buffer testing

                              Yes.
                              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

                              • topfli8979
                                Badcaps Veteran
                                • Oct 2012
                                • 311
                                • USA

                                #16
                                Re: vp50hdtv10a Buffer testing

                                Alright -vy is up -200, +vsc 120. Should I just go for it and run the set, these y boards are so expensive. Nothing else I need to test?

                                Comment

                                • tom66
                                  EVs Rule
                                  • Apr 2011
                                  • 32560
                                  • UK

                                  #17
                                  Re: vp50hdtv10a Buffer testing

                                  Just run it.
                                  As SOON as it starts flickering, cut it off.
                                  If it doesn't short then, no damage done.
                                  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

                                  • topfli8979
                                    Badcaps Veteran
                                    • Oct 2012
                                    • 311
                                    • USA

                                    #18
                                    Re: vp50hdtv10a Buffer testing

                                    So far so good, but I am getting red and green sporadic pixelation ONLY in the upper left hand corner of the screen. I know the tv is 6 years old, have seen it on numerous plasma sets. But not in just one corner.

                                    Comment

                                    • tom66
                                      EVs Rule
                                      • Apr 2011
                                      • 32560
                                      • UK

                                      #19
                                      Re: vp50hdtv10a Buffer testing

                                      Yeah, that indicates incorrect Vsc or -Vy, or Setup/Setdn timings, as it ages, you may need to tweak these voltages slightly but NO more than 10V should be necessary.

                                      Sometimes it cannot be resolved without firmware updates made to the control board.
                                      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

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