Vizio VS420LF1A, no sound, no backlight and no pic.

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  • dmesser100
    Senior Member
    • Oct 2011
    • 53
    #1

    Vizio VS420LF1A, no sound, no backlight and no pic.

    from what i can tell so far, im not getting 12volts from the power board when the tv is turned on. i get all other voltages, like 5v and the 2volt for the inverter on/off. here is the power board, its the kind that powers inverters all in one i think. can anyone point me in the right direction? thanks
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    • dmesser100
      Senior Member
      • Oct 2011
      • 53
      #2
      Re: Vizio VS420LF1A, no sound, no backlight and no pic.

      ok, if i leave it unpluged for a day or so. it will power up fine. Im pretty stumped, maybe a cold solder somewhere?

        Comment

        • tom66
          EVs Rule
          • Apr 2011
          • 32560
          • UK
          #3
          Re: Vizio VS420LF1A, no sound, no backlight and no pic.

          When you do get it to power on, make sure to turn the sound up and select a working source. Wait for it to fail, do you get sound in the failed state?
          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

            • dmesser100
              Senior Member
              • Oct 2011
              • 53
              #4
              Re: Vizio VS420LF1A, no sound, no backlight and no pic.

              does get sound in faild state tom66, what does this mean?

                Comment

                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK
                  #5
                  Re: Vizio VS420LF1A, no sound, no backlight and no pic.

                  It means the main board is working fine but you are losing the backlight power. Therefore, concentrate any soldering work around the backlight transformers, their connections and the heatsink with the driver FETs on it. (this is the one near the two backlight transformers.)
                  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

                    • dmesser100
                      Senior Member
                      • Oct 2011
                      • 53
                      #6
                      Re: Vizio VS420LF1A, no sound, no backlight and no pic.

                      my sister says it still gets sound when the pic goes out. will check it for myself and get back out the solder iron if it does. thanks, will post back soon

                        Comment

                        • dmesser100
                          Senior Member
                          • Oct 2011
                          • 53
                          #7
                          Re: Vizio VS420LF1A, no sound, no backlight and no pic.

                          ok, it does not get backlight or data to the screen. and it does not get 12v from the power board. does get 2.5v on the ps on/off and 5v where its supposed to have output. how can i get the 5v and not the 12 from the board?

                            Comment

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