lcd picture faded to black

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  • attenuator1222
    Member
    • Jan 2013
    • 12
    • uk

    #1

    lcd picture faded to black

    i got the tcon board on my desk in front of me now
    ive just ordered a new identical one off ebay
    http://s14.postimage.org/6oedtkwi9/tcon.jpg
    just for the hell of it are there any tests i can do on this board to find out what went wrong?
    thanks
    i checked the fuse and its fine ,zero ohm
    i was watching tv and the image slowly started to fade to black
    i can see the backlight and audiio is fine
    Last edited by attenuator1222; 01-21-2013, 08:15 PM. Reason: additional info
  • randtek
    Badcaps Veteran
    • Oct 2011
    • 280
    • US

    #2
    Re: lcd picture faded to black

    Other than measuring the values of resistors, checking diodes for shorts etc., no there is no way to diagnose. I have not seen any panel manufacturer even release schematics of a T-Con board. Even with schematics, you would need to be able to power up the board and supply LVDS data to it to be able to test any of the integrated circuits.

    Comment

    • selldoor
      Slow Learner
      • Dec 2010
      • 7870

      #3
      Re: lcd picture faded to black

      Why did you think the tcon was the problem?

      Welcome to the forum-
      We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back (in the same orientation) and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

      Please do not post inline and offsite as they slow down the loading of pages.

      Examples of what is needed

      https://www.badcaps.net/forum/attach...7&d=1280167246

      https://www.badcaps.net/forum/attach...6&d=1280167246

      https://www.badcaps.net/forum/attach...4&d=1280167246

      It will be useful if you can say a bit about yourself - skills tools etc.
      Please upload pictures using attachment function when ask for help on the repair
      http://www.badcaps.net/forum/showthread.php?t=39740

      Comment

      • attenuator1222
        Member
        • Jan 2013
        • 12
        • uk

        #4
        Re: lcd picture faded to black

        i assumed it was the tcon from what i have read from other forums
        im uploading photos now
        so it could easily be something else?
        i have some tools no scope an hnc in electronics

        Comment

        • gilly1984
          Badcaps Veteran
          • Jun 2012
          • 751
          • UK

          #5
          Re: lcd picture faded to black

          Did you check the voltage to the tcon? Could be bad cap on psu.
          Do NOT touch heatsinks when testing for voltages as they may be LIVE!

          Comment

          • drpj23
            Badcaps Veteran
            • May 2012
            • 528
            • USA

            #6
            Re: lcd picture faded to black

            As long as the voltages check out going to the TCON this could be a heat related problem and freeze/dust spray could find the faulty component(s) on that board (granted it is that board).

            Comment

            • attenuator1222
              Member
              • Jan 2013
              • 12
              • uk

              #7
              Re: lcd picture faded to black

              here are some snaps
              so you think i was rash in ordering the tcon board?
              Attached Files

              Comment

              • attenuator1222
                Member
                • Jan 2013
                • 12
                • uk

                #8
                Re: lcd picture faded to black

                Originally posted by gilly1984
                Did you check the voltage to the tcon? Could be bad cap on psu.
                what kind of voltage level am i looking for?

                Comment

                • selldoor
                  Slow Learner
                  • Dec 2010
                  • 7870

                  #9
                  Re: lcd picture faded to black

                  Cant quite read is the fuse rated for 32v? Board voltage is usually 12 or 24.
                  set your meter on 200vDC
                  Please upload pictures using attachment function when ask for help on the repair
                  http://www.badcaps.net/forum/showthread.php?t=39740

                  Comment

                  • selldoor
                    Slow Learner
                    • Dec 2010
                    • 7870

                    #10
                    Re: lcd picture faded to black

                    Pictures are too fuzzy for troubleshooting. Probably need to be better lit but without flash.
                    Please upload pictures using attachment function when ask for help on the repair
                    http://www.badcaps.net/forum/showthread.php?t=39740

                    Comment

                    • attenuator1222
                      Member
                      • Jan 2013
                      • 12
                      • uk

                      #11
                      Re: lcd picture faded to black

                      Originally posted by selldoor
                      Cant quite read is the fuse rated for 32v? Board voltage is usually 12 or 24.
                      set your meter on 200vDC
                      yes it is
                      i took 2 measurements of just over 5v from either sides of the fuse and the metal chassis with the tv powered on

                      Comment

                      • selldoor
                        Slow Learner
                        • Dec 2010
                        • 7870

                        #12
                        Re: lcd picture faded to black

                        What is the part number on the Tcon board
                        Please upload pictures using attachment function when ask for help on the repair
                        http://www.badcaps.net/forum/showthread.php?t=39740

                        Comment

                        • attenuator1222
                          Member
                          • Jan 2013
                          • 12
                          • uk

                          #13
                          Re: lcd picture faded to black

                          Originally posted by selldoor
                          what is the part number on the tcon board
                          cpwbx3919tp

                          Comment

                          • gilly1984
                            Badcaps Veteran
                            • Jun 2012
                            • 751
                            • UK

                            #14
                            Re: lcd picture faded to black

                            Originally posted by attenuator1222
                            yes it is
                            i took 2 measurements of just over 5v from either sides of the fuse and the metal chassis with the tv powered on
                            did You measure after it fades too?
                            Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                            Comment

                            • attenuator1222
                              Member
                              • Jan 2013
                              • 12
                              • uk

                              #15
                              Re: lcd picture faded to black

                              Originally posted by gilly1984
                              did You measure after it fades too?
                              sorry i dont follow
                              the tv faded to black one day while i was watching it (sound still there)
                              now when i turn it on i get the glow from the backlight and sound
                              the measurements i took were with the tv powered on with the backlight glowing

                              Comment

                              • nomoresonys
                                Badcaps Legend
                                • Jan 2013
                                • 12123
                                • U.S.

                                #16
                                Re: lcd picture faded to black

                                sounds like a bad inverter.

                                Comment

                                • attenuator1222
                                  Member
                                  • Jan 2013
                                  • 12
                                  • uk

                                  #17
                                  Re: lcd picture faded to black

                                  Originally posted by nomoresonys
                                  sounds like a bad inverter.
                                  its not the backlight is working

                                  Comment

                                  • gilly1984
                                    Badcaps Veteran
                                    • Jun 2012
                                    • 751
                                    • UK

                                    #18
                                    Re: lcd picture faded to black

                                    Ah sorry, i read it wrong.

                                    Just found this via a google search

                                    "One trick to check most TCONS for functionality is to loosen the LVDS connector at the TCON (as shown InFigure 3) while the unit is turned on. Handle the LVDS connector with care and be certain to fully release the locktabs. Gently rock the cable in and out of the connector while observing the screen for any response. Dependingon the chassis, the symptoms of the screen may be gentle white flashes, intermittent colored lines, or a screenfull of random patterns. The idea at this point is to provoke some kind of response on the screen. TCON boardsthat have failed will not usually generate any type of response on the screen."

                                    Worth a try.
                                    Attached Files
                                    Do NOT touch heatsinks when testing for voltages as they may be LIVE!

                                    Comment

                                    • attenuator1222
                                      Member
                                      • Jan 2013
                                      • 12
                                      • uk

                                      #19
                                      Re: lcd picture faded to black

                                      Originally posted by gilly1984
                                      Ah sorry, i read it wrong.

                                      Just found this via a google search

                                      "One trick to check most TCONS for functionality is to loosen the LVDS connector at the TCON (as shown InFigure 3) while the unit is turned on. Handle the LVDS connector with care and be certain to fully release the locktabs. Gently rock the cable in and out of the connector while observing the screen for any response. Dependingon the chassis, the symptoms of the screen may be gentle white flashes, intermittent colored lines, or a screenfull of random patterns. The idea at this point is to provoke some kind of response on the screen. TCON boardsthat have failed will not usually generate any type of response on the screen."

                                      Worth a try.
                                      hi should of mentioned i tried that as well no change
                                      ive already ordered the replacement now just my luck it wont be the tcon in which case i will skip tv

                                      Comment

                                      • nomoresonys
                                        Badcaps Legend
                                        • Jan 2013
                                        • 12123
                                        • U.S.

                                        #20
                                        Re: lcd picture faded to black

                                        my bad, read it wrong, I thought it read went completely black, gilly is right if no light reaction when tcon is rocked, then more than likely the tcon or tcon cable.

                                        Comment

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