JVC LT48N530A no image or sound power supply OK

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  • dkneyle
    Badcaps Veteran
    • Dec 2013
    • 441
    • Australia
    #1

    JVC LT48N530A no image or sound power supply OK

    This is a Chinese clone or re-badge despite the JVC name.

    No image or sound. Nothing visible with the flashlight test. Tried accessing HDMI ports and playing a movie with no signs of audio output. Voltages on power supply seem to come up OK. The LED tell-tale on the front of the TV reacts to remote button control and goes from red to green in an expected manner.

    The LED backlight voltage gives a clue. At initial power-on it is sitting at about 35VDC. Then it briefly goes up to about 150VDC (about what I'd expect) before quickly cascading back down to ~35VDC.

    So, do you reckon I have failed LED string in the panel? If so, why can't I see an image with the flashlight test or get some sort of audio output via the HDMI port?

    There is secondhand mainboard available for sale but I'm reluctant to invest in that if I actually have a defective panel.
    Tags: None
    • Andrew F. Ali
      Badcaps Legend
      • Jan 2014
      • 2450
      • Trinidad & Tobago
      #2
      Re: JVC LT48N530A no image or sound power supply OK

      That sounds like a bad/open backlight string/s. Don't worry about not seeing anything with the flashlight test. Try looking when the menu is up. Sometimes it escapes us to see the flashlight test work.

        Comment

        • dkneyle
          Badcaps Veteran
          • Dec 2013
          • 441
          • Australia
          #3
          Re: JVC LT48N530A no image or sound power supply OK

          Any other votes confirming it's likely to be a failed LED string in the panel?

            Comment

            • R_J
              Badcaps Legend
              • Jun 2012
              • 9514
              • Canada
              #4
              Re: JVC LT48N530A no image or sound power supply OK

              At the time the voltage went to 150vdc you would see the backlight if it was working, so very likely open led.

                Comment

                • dkneyle
                  Badcaps Veteran
                  • Dec 2013
                  • 441
                  • Australia
                  #5
                  Re: JVC LT48N530A no image or sound power supply OK

                  Yes RJ, not even a flash from the LEDs. I did tell the seller that it was my suspicion and therefore she needed to accept there was little value in the set other than a few spare parts. Thanks all. Time to strip it down I think.

                    Comment

                    • R_J
                      Badcaps Legend
                      • Jun 2012
                      • 9514
                      • Canada
                      #6
                      Re: JVC LT48N530A no image or sound power supply OK

                      Check for a bad led, It might only need one replaced, might be an easy repair

                        Comment

                        • dkneyle
                          Badcaps Veteran
                          • Dec 2013
                          • 441
                          • Australia
                          #7
                          Re: JVC LT48N530A no image or sound power supply OK

                          Just to close off the thread, I stripped it down, and checked the LED strips. 3 failed LEDs in total. So it was a panel fault.

                            Comment

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