42LG5000-ZA getting dark after 10 minutes

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  • Smasher
    Member
    • May 2015
    • 11
    • Austria
    #1

    42LG5000-ZA getting dark after 10 minutes

    Hi,

    my 42LG5000 TV suddenly started getting very dark, as if I would turn down the backlight in the menu, but even darker than it would be on the lowest level.

    This happens about 10 minutes after switching the TV on. The first 10 minutes the picture quality is as I'm used to.

    I've already opened the device checking for obvious bad parts, but haven't seen any.

    Some pictures of T-Con board, backlight inverter (master + slave) and the whole device are attached.

    Hope somebody can point me in the right direction.

    Thanks in advance!

    Flo
    Attached Files
    Tags: None
    • newtothis
      Badcaps Legend
      • Mar 2013
      • 1556
      • england
      #2
      Re: 42LG5000-ZA getting dark after 10 minutes

      Can you get us a picture of normal vs dark?

        Comment

        • Smasher
          Member
          • May 2015
          • 11
          • Austria
          #3
          Re: 42LG5000-ZA getting dark after 10 minutes

          Here you are..
          Attached Files

            Comment

            • victor_cj
              Senior Member
              • May 2015
              • 90
              • Romania
              #4
              Re: 42LG5000-ZA getting dark after 10 minutes

              In this case it is possible to have insulation problem at CCFL PCB.
              Attached Files
              The art of fighting without fighting

                Comment

                • newtothis
                  Badcaps Legend
                  • Mar 2013
                  • 1556
                  • england
                  #5
                  Re: 42LG5000-ZA getting dark after 10 minutes

                  Can't see there being an issue with insulation TBH

                  Ok couple of tests

                  First can you attach the TV to a PC or similar and use something like notepad to produce a completely white screen... Have a look for any darker areas when it faults.

                  Secondly can you get a hairdryer and heat up a board at a time to see if the fault occurs quicker, Start with the Tcon then the Main

                    Comment

                    • Smasher
                      Member
                      • May 2015
                      • 11
                      • Austria
                      #6
                      Re: 42LG5000-ZA getting dark after 10 minutes

                      The Picture "1.jpg" show the white screen when the TV is switched on, then after about 6 minutes it starts getting those vertical lines with flickering horizontal ones, as can be seen on picture "2.jpg".

                      I tried with the hair dryer, it's definitely the T-Con when getting hot, the error can be seen after 1-2 minutes of heating it up. Hair dryer on the main board didn't show that effect.

                      Thanks again!
                      Attached Files

                        Comment

                        • newtothis
                          Badcaps Legend
                          • Mar 2013
                          • 1556
                          • england
                          #7
                          Re: 42LG5000-ZA getting dark after 10 minutes

                          Replace TCON

                          No Problem

                            Comment

                            • Smasher
                              Member
                              • May 2015
                              • 11
                              • Austria
                              #8
                              Re: 42LG5000-ZA getting dark after 10 minutes

                              Ok, will do!

                              Will report back if it fixed the problem!

                              Thank you very much!

                                Comment

                                • victor_cj
                                  Senior Member
                                  • May 2015
                                  • 90
                                  • Romania
                                  #9
                                  Re: 42LG5000-ZA getting dark after 10 minutes

                                  AS15-F fault or COF from LCD screen with bonding problem.
                                  The art of fighting without fighting

                                    Comment

                                    • newtothis
                                      Badcaps Legend
                                      • Mar 2013
                                      • 1556
                                      • england
                                      #10
                                      Re: 42LG5000-ZA getting dark after 10 minutes

                                      Originally posted by victor_cj
                                      AS15-F fault or COF from LCD screen with bonding problem.
                                      Yeah AS15 fault.

                                      Got a couple of those Tcons here that had failed AS15... One the usual lighter screen and one with a darker screen

                                        Comment

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