Vizio M420SL Backlight Issue

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  • Gadjet
    Badcaps Veteran
    • Aug 2012
    • 248
    • United States
    #1

    Vizio M420SL Backlight Issue

    Just picked up this unit the previous owner said one day he turned it on and he didn't get any video but he had sound. When I plugged it in it had audio and video (pic 1). After about 10-15 mins the backlights went out, the flashlight test shows a picture still running in the background. I disassembled the unit and tested the lights with my backlight tester seems to be just one strip of lights running down the left side of the screen. Each section of the strip I tested showed no sign of an individual led being out. So my question is does it sound like a led or power supply issue or could it still be the Led strip?
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    • nomoresonys
      Badcaps Legend
      • Jan 2013
      • 12128
      • U.S.
      #2
      Re: Vizio M420SL Backlight Issue

      Turn the backlights NOT brightness down and see if you get longer times before they go out.

        Comment

        • tmwalsh
          Senior Member
          • Jan 2009
          • 119
          #3
          Re: Vizio M420SL Backlight Issue

          NoMore is suggesting changing the load on the backlight power supply by demanding less to see if the power supply will totter on for a while longer with less demand.
          If there are no shorts in the diodes, the supply is likely the problem area. You could measure the amps required by the strings to see if they are more than nominal.
          tom

            Comment

            • Gadjet
              Badcaps Veteran
              • Aug 2012
              • 248
              • United States
              #4
              Re: Vizio M420SL Backlight Issue

              Thanks for the suggestions, I will put it back together and post the results.

                Comment

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