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42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

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    42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

    Hi all

    Issue seems to be slightly tap sensitive , although that might be a complete coincidence .

    Main board problem none the less .

    Can anyone advise .

    I'm leaning toward re-balling the main BGA processor chip .

    Have the correct stencil in stock , therefore must have re-balled one of these chips in the distant past .
    Attached Files

    #2
    Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

    All signs point to BGA, I have one of these boards from a 42LM6400, after reflowing the main chip it lasted for 2 years, then further reflow attempts failed to make the TV last even 1 minute powered on.

    But the TV should not freeze, it should power off immediately or not even get out of standby when it's the main chip.

    Comment


      #3
      Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

      Thanks for the input .

      I don't tend to re - flow any more , as it doesn't seem to be reliable .

      Will re - ball & report back

      Comment


        #4
        Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

        On removal & inspection of BGA , may have worked out issue .

        part of track , which looks to be a through hole point seems to have been exposed , by heat from the a capacitor that sits directly under it .

        Could try some solder mask to insulate point then fit chip back .

        Although it looks like it from picture it's not a pad .
        Attached Files

        Comment


          #5
          Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

          Re-ball seems to have gone really well , & solder mask to took exposed track .
          Attached Files

          Comment


            #6
            Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

            Well i'm genuinely surprised .

            Set powers & now working on a test .

            Lets see how it behaves , or not a the case may be .

            Comment


              #7
              Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

              Nice job on the reballing process, hope it fixes it.

              Comment


                #8
                Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

                Thanks again

                Comment


                  #9
                  Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

                  Reballed a Vizio a couple years ago. Still working in the living room.
                  I assume no responsibility for any stupid suggestions I might post.

                  Comment


                    #10
                    Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

                    Nice one, yes re-balling rather than re-flowing seems to be the way to go for me .

                    Have been experimenting for a few years now & have quite a reliable technique with the equipment i use .

                    Many re-balling videos on You Tube .

                    Comment


                      #11
                      Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

                      I think leaded solder is superior to the brittle unleaded. Military still uses leaded solder for reliability.
                      I assume no responsibility for any stupid suggestions I might post.

                      Comment


                        #12
                        Re: 42LM670TZA , picture freezing , then powers off , or hanging on LG logo .

                        Most definitely .

                        Aviation also , & quite possibly medical equipment .

                        More work for us i suppose

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