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    #1

    Grunding TV flickering picture

    Hi guys, I got this Grunding TV set that at first didn't want to turn on only one quick flash of backlight and back to off. Voltages on PSU are okay, +24V, +12V +5V stby etc. LED inverter gives +89V and the LED's work bright.

    Anyhow after disasembling the screen and forcing BL-ON and seeing that LED backlight is okay (no burned leds) TV decided to start working but the picture is flickering when on.

    Anyone had a similar issue, my only thought is that there is a Cap with high ESR or shorted and me starting it kind made some of his life to come back

    Video below:
    https://www.youtube.com/watch?v=fUycJ5keOVM
    Tags: None
    #2
    Re: Grunding TV flickering picture

    We need some pictures of your boards, model number of your TV etc.

    When your TV flickers like that, what does BLon do? Try to turn down your backlights and brightness as far as it goes. See if it still flickers.

    Does your TV have an automatic backlight adjust (for when its daylight or night time) turn that off.

    Comment

      #3
      Re: Grunding TV flickering picture

      Okay, left the TV to cool off - naturally it wouldn't turn on at first. After letting it warm up for 5 minutes (it tries turning the backlight but fails after 1 sec) eventually it turned the backlight on but still no picture.
      After heating the Caps on mainboard using hot air gun it started and works great. Backlight on, no screen flicker.

      BL_ON is 2.8V (when the backlight is on), 0V when off.

      Motherboard model: YNG190R-12
      Inverter model: INV32L04

      Some pictures:


      Comment

        #4
        Re: Grunding TV flickering picture

        Looks like a Beko chassis, I would suggest checking all the small regulators Ive had a Beko Lcd mainboard where it was stuck in standby which was due to a failed 1.2v reg.
        Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

        https://www.facebook.com/Telford-Tel...7894576335359/

        Comment

          #5
          Re: Grunding TV flickering picture

          Quick update:
          Left the TV on for 5 minutes and it lost picture - but backlight is on.
          Reheated the mainboard and the picture came back, so definitively an error in that area

          Gonna dig some more, maybe replace the caps and reflow the main ic. Cheers!

          Comment

            #6
            Re: Grunding TV flickering picture

            sounds like bad caps to me.

            Comment

              #7
              Re: Grunding TV flickering picture

              Update: Checked all caps, esr is between 0.3 - 0.7, also replaced 3 main ones on mainboard - didn't help.

              Tried reflowing the main IC chip, didn't help. Picture is okay only when the main IC is hot (heated with hot air gun)...

              Looks like defective mainboard chip

              Comment

                #8
                Re: Grunding TV flickering picture

                That sux. Well... I guess you're in for a new main board!

                Comment

                  #9
                  Re: Grunding TV flickering picture

                  Before you order a new main check low voltage regulators around the processor. You may be lucky to have one of those at fault and not the processor.
                  Originally posted by PeteS in CA
                  Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                  A working TV? How boring!

                  Comment

                    #10
                    Re: Grunding TV flickering picture

                    Originally posted by Th3_uN1Qu3 View Post
                    Before you order a new main check low voltage regulators around the processor. You may be lucky to have one of those at fault and not the processor.

                    Thanks will do that

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