Grunding TV flickering picture

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  • 6ot4hr
    Senior Member
    • Oct 2014
    • 87
    • Croatia
    #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
    • CapLeaker
      Leaking Member
      • Dec 2014
      • 8000
      • Canada
      #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

        • 6ot4hr
          Senior Member
          • Oct 2014
          • 87
          • Croatia
          #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

            • ReeceyBurger123
              Never Give Up !
              • May 2014
              • 7325
              • Britain
              #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

                • 6ot4hr
                  Senior Member
                  • Oct 2014
                  • 87
                  • Croatia
                  #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

                    • CapLeaker
                      Leaking Member
                      • Dec 2014
                      • 8000
                      • Canada
                      #6
                      Re: Grunding TV flickering picture

                      sounds like bad caps to me.

                        Comment

                        • 6ot4hr
                          Senior Member
                          • Oct 2014
                          • 87
                          • Croatia
                          #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

                            • CapLeaker
                              Leaking Member
                              • Dec 2014
                              • 8000
                              • Canada
                              #8
                              Re: Grunding TV flickering picture

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

                                Comment

                                • Th3_uN1Qu3
                                  Believe in
                                  • Jul 2010
                                  • 6031
                                  • Romania
                                  #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

                                    • 6ot4hr
                                      Senior Member
                                      • Oct 2014
                                      • 87
                                      • Croatia
                                      #10
                                      Re: Grunding TV flickering picture

                                      Originally posted by Th3_uN1Qu3
                                      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

                                        Comment

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