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Insignia NS-37D20SNA14 intermittent LEDs

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    Insignia NS-37D20SNA14 intermittent LEDs

    So I use this TV daily as a second monitor for my PC or my Playstation - at one point a few months back I tried to fix the problem - but in the process, I figured out something that works so I haven't posted this for awhile. It is an annoying trick to have to do though, so I decided to post about it to see if anyone could spot what's wrong. It baffles me because it works on it's own half the time.

    When I first got this TV, I was told it wouldn't turn on, and of course I did the flashlight test, and the image was there. Also, the red LED on the front indicated that it had power (it goes off when powered on, and is red in standby). The LED driver being on the power supply board on this model, there's basically the input/audio board and the power board. So that's first thing I replaced is the power board from a reputable seller with good reviews. (6MY0112010) The problem didn't change at all. I tried leaving the TV on for hours, with a bright image, a dull image, nothing worked. Unplugging, plugging back in, usual tests. There is actually a very faint flicker on the screen every few seconds - but it's so dim that you have to be sorta looking away from the TV to notice it.

    Now here's what's weird. I probably took the back of the TV off 5 or 6 times while working on it. Many times I thought I had solved the issue - because EVERY single time I reassembled the TV and turned it on, it worked like a charm. Until I turned it off. Even after just turning it off, the LEDs would not work more than once. It took quite awhile to figure out that every time I had it open, I would put my 300v LED tester to the whole array - and they would light up fine. That's why it worked ONCE when I put it back together. It really threw me off.

    So that is how it is now. Almost every time I turn it on - black screen. So I made a very small hole in the back case, right over where the LEDs plug into the power board. It wasn't that difficult since there is a cooling vent there. I will unplug the TV, and light up the LEDs with the tester. Plug the TV back in - and it works 100% of the time. Here is something weird though - if I turn the TV off when it is on the input of the Playstation (HDMI 1), and before I turn the TV on again, I turn on the Playstation, the TV works a lot of the time when I turn it on without doing the LED tester thing. I thought that maybe that had something to do with the brightness of the PS menu screen - but it doesn't do that when I turn it on with the second PC monitor (HDMI 2) selected. No matter what bright image I put on the screen. So I can make it work by making sure it's on the Playstation input before I turn it off, the turn on the Playstation before I turn the TV back on - but that is a real hassle as I use it mostly for the 2nd PC monitor. And I have to do this every time my PC sleeps.

    But basically the issue is this - once it is on, there are no problems and the picture is beautiful. But most of the time I have to unplug it and manually light up the LEDs through the back panel with a 300v tester, plug it back in to make the LEDs work. What do you think that could be? Is it some capacitor that is just on it's last legs? Some kind of weird intermittent short in one of the LEDs? In one of the strips? What would lighting up the LEDs from an external source change on an individual LED or strip? None of the caps were bulging or looked bad in any way - and like I said I changed the whole board anyway, and it still did this, identicall with a new board, and now with the original board back in. When it is working it, it doesn't matter if it's on 5 minutes or 10 hours, if you turn it off, it won't come back without the LEDs lit up manually through the back - except weirdly - it will work (probably 75% of the time) if it's on the input of the PS and the PS is on.....

    Thanks for reading my book LOL
    Last edited by THE GTC; 11-03-2020, 02:57 AM.

    #2
    Re: Insignia NS-37D20SNA14 intermittent LEDs

    What happen if you turn down the backlights level, Not Brightness, to below 50% for all inputs and also turn off any automatic ambient backlights setting?

    LED tester only puts out 39mA, not 200 ~ 400mA in TV normal operating level, so tester may not show the problem if some of the LED's are weak, or bad connectors that link the LED strips when LED's are driven at high power.
    Never stop learning
    Basic LCD TV and Monitor troubleshooting guides.
    http://www.badcaps.net/forum/showthr...956#post305956

    Voltage Regulator (LDO) testing:
    http://www.badcaps.net/forum/showthr...999#post300999

    Inverter testing using old CFL:
    http://www.badcaps.net/forum/showthr...er+testing+cfl

    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
    http://s807.photobucket.com/user/budm/library/

    TV Factory reset codes listing:
    http://www.badcaps.net/forum/showthread.php?t=24809

    Comment


      #3
      Re: Insignia NS-37D20SNA14 intermittent LEDs

      Wow I feel really dumb! The brightness was set to 55/100. The backlight was set to 45/50. I was in these settings so long ago, I didn't even think to look again in the settings - in my mind that was only one setting. Also, because I had to order a remote that I only got a little while ago.

      So... I just now left the brightness at 55/100, but set the backlight to 20/50. The TV turned on 5 times in a row, the again turned on 10 minutes later.

      Mark this solved. Thank you very much and great catch about the brightness I mentioned. I do feel ashamed though at not rechecking the settings.

      And I do type fast. LOL Thanks again. This site is invaluable.
      Last edited by THE GTC; 11-03-2020, 03:07 AM.

      Comment


        #4
        Re: Insignia NS-37D20SNA14 intermittent LEDs

        And I mean solved by - this is a good enough fix. I don't need full brightness, until it poops - I can afford TVs and have others - I really just like figuring it out too and it was a shame to have it already mounted, knowing it works great when they light up... plus I used it as an opportunity to get into some amateur repair and bought a few little gadgets

        Comment


          #5
          Re: Insignia NS-37D20SNA14 intermittent LEDs

          If the images look good enough for now with low backlights setting, I would keep using it until the LED's fail completely then you can deal with taking apart the LCD panel later, taking the panel apart is the last thing you want to do since it can easily be damaged.
          Never stop learning
          Basic LCD TV and Monitor troubleshooting guides.
          http://www.badcaps.net/forum/showthr...956#post305956

          Voltage Regulator (LDO) testing:
          http://www.badcaps.net/forum/showthr...999#post300999

          Inverter testing using old CFL:
          http://www.badcaps.net/forum/showthr...er+testing+cfl

          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
          http://s807.photobucket.com/user/budm/library/

          TV Factory reset codes listing:
          http://www.badcaps.net/forum/showthread.php?t=24809

          Comment

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