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    LCD Tab bond fix.

    My first post so be kind guys.

    After retiring I've taken up a bit of TV repair and am amazed how helpful forums like this are and how much help there is out there.

    I've recently got a Toshiba 37” TV with extreme ghosting problems, the fault was so bad that there was no chance of even working through the menus to tune it in. All indications pointed to the poor bonding of the TAB bonds to the LCD display.

    I've read many posts about placing some packing material on the LCD Tab bond where the flexprint connects to the pcb but wanted to try to effectively re-solder the connections. Here is how I managed it.

    1. Take some ordinary kitchen grease proof paper and fold it in half to achieve double thickness.
    2. Place it over the flexprint where it connects to the pcb.
    3. Rub your soldering iron quickly back and forth in a circular pattern over the grease proof paper on top of the connections. Cover about 5mm of the connector at a time before moving along the connector to the end.

    That's it.
    The idea of the paper is to reduce the direct heat to the connection by dissipating it somewhat while heating the connection just enough to do the job.

    Take great care not to touch the flexprint with the soldering iron directly as it is possible to burn it and destroy it completely. Modern cables are quite robust and will be ok but be on the safe side and take your time.

    I did have to do this twice as the first time I cured the fault but found a slight intermittent dimming on part of the display. After a second time all faults disappeared.
    As a precaution I will also add some packing material to try to stop the fault from re-occurring.

    Good luck everyone.

    I hope this is all clear, all questions, comments or criticisms welcome.
    Tim

    #2
    Re: LCD Tab bond fix.

    Hi,

    I have a question about the grease proof kitchen paper you used in the repair.
    Is it the same as parchment paper in the US?
    It is a brown paper that is impregnated with silicone (I think) and can withstand higher temperatures in the oven. Used for baking, etc.

    Thanks,
    Mike

    Comment


      #3
      Re: LCD Tab bond fix.

      Hi Timall!

      I'm very intrigued by your repair technique.

      I see that most people are using something to shim the TABs. I think I ran across one other attempt where someone suggested using a clothing iron (without water/steam).
      The idea that an otherwise perfectly working LCD panel is “junk” because of a signal cable delaminating from the PCB is just asinine to me. In the absence of a more reliable assembly method, I’d like to see a more reliable repair option available.

      To build on your technique, I’m wondering if something like this would be reliable… I have a Trim Sealing Iron used to adhere the plastic covering on model aircraft. It is kind of like a soldering iron, but with a flatter tip (similar to a clothing iron) and has a temperature control.

      Here is an example of the tool. Thoughts?
      http://www.coverite.com/accys/covr2750.html

      Comment


        #4
        Re: LCD Tab bond fix.

        I have read somewhere that these tabs are heat bonded, using some special adhesive to bond the tab to the glass surface.
        Somewhere on the net, I have found people using a T tip, with silicon or Teflon edge, on the soldering iron to heat up the tab.

        Comment


          #5
          Re: LCD Tab bond fix.

          do the newer led tvs have the tab bond issues like the lcds do?, Thanks.

          Comment


            #6
            Re: LCD Tab bond fix.

            I was thinking something similar, but more along the lines of a clamp to cover and put even pressure on the whole tab while heating the driver IC.

            I think that you can also use a couple layers of kapton tape to protect the driver from excessive heat instead of the aforementioned paper.

            Edit: To answer the question above that has been posted in the meantime: Yes, new LED panels suffer from it too. Actually it's gotten worse, as LEDs allow the screens to be made thinner and thus are even more fragile than the older ones.
            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


              #7
              Re: LCD Tab bond fix.

              Originally posted by Th3_uN1Qu3 View Post
              I was thinking something similar, but more along the lines of a clamp to cover and put even pressure on the whole tab while heating the driver IC.

              I think that you can also use a couple layers of kapton tape to protect the driver from excessive heat instead of the aforementioned paper.

              Edit: To answer the question above that has been posted in the meantime: Yes, new LED panels suffer from it too. Actually it's gotten worse, as LEDs allow the screens to be made thinner and thus are even more fragile than the older ones.
              that the last straw, I'm going back to crt, I can get a boatload for free, every junk day.

              Comment


                #8
                Re: LCD Tab bond fix.

                Hi Guys, sorry for not replying to any posts, I failed to set the thread tools to let me know of any replies and thought no one had replied.

                1. Yes I think the grease proof paper I used would be the same as parchment paper in the US
                2. Yes newer led televisions still suffer the same problem.
                3. I think the kapton tape is also a good method of reducing the direct temperature to the Tab Bond.
                4. ChrisTheHokie This does looks intriguing http://www.coverite.com/accys/covr2750.html I'd be interested how you get on with it.

                Some good ideas so far and anything is worth a try. I've just managed to repair a 37” Samsung LED TV with this method. I found a problem with a Tab Bond to one of the little chips down the side of the screen; I hadn't realised the chips were there before. When applying heat to the actual chips they will need to be supported from the other side as they are quit brittle and are easily broken.
                So far the TV has been working flawlessly for a couple of weeks now.

                Good luck with your own efforts.

                Comment


                  #9
                  Re: LCD Tab bond fix.

                  This is what I use: The 52" SONY and SAMSUNG are still good after almost 3 years.
                  https://www.badcaps.net/forum/showth...LN52A530P1FXZA

                  https://www.badcaps.net/forum/showthread.php?t=37887

                  https://www.badcaps.net/forum/showthread.php?t=37885
                  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


                    #10
                    Re: LCD Tab bond fix.

                    Question regarding Sony Bravia tab bond:

                    Is the metal frame (last piece you remove to get to tabs) OK to modify? I mean, it seems like it's designed to press the tab ribbons in (dimples in metal).

                    I had to flatten the dimples so they wouldn't press against (touch) the ribbon. It doesn't like act as a heatsink or anything?
                    Last edited by rustytierod; 03-28-2017, 02:25 AM.

                    Comment


                      #11
                      Re: LCD Tab bond fix.

                      ignore..
                      Last edited by heavymachines; 03-28-2017, 11:35 PM. Reason: details

                      Comment

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