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

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  • zen
    Badcaps Veteran
    • Apr 2011
    • 511

    #1

    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
  • Biruslapio
    Badcaps Veteran
    • Nov 2013
    • 552
    • Brasil

    #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

    • zen
      Badcaps Veteran
      • Apr 2011
      • 511

      #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

      • zen
        Badcaps Veteran
        • Apr 2011
        • 511

        #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

        • zen
          Badcaps Veteran
          • Apr 2011
          • 511

          #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

          • zen
            Badcaps Veteran
            • Apr 2011
            • 511

            #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

            • Biruslapio
              Badcaps Veteran
              • Nov 2013
              • 552
              • Brasil

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

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

              Comment

              • zen
                Badcaps Veteran
                • Apr 2011
                • 511

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

                Thanks again

                Comment

                • dskall
                  Badcaps Legend
                  • Oct 2016
                  • 2905
                  • usa

                  #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

                  • zen
                    Badcaps Veteran
                    • Apr 2011
                    • 511

                    #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

                    • dskall
                      Badcaps Legend
                      • Oct 2016
                      • 2905
                      • usa

                      #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

                      • zen
                        Badcaps Veteran
                        • Apr 2011
                        • 511

                        #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

                        Comment

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