testing a main board

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  • sarah2010
    New Member
    • Dec 2019
    • 6
    • United Kingdom

    #1

    testing a main board

    hi all

    i have an LG 60pb690v which im trying to diagnose with no luck up to now, i have replaced zsus, ysus and power board. A little more research shows the issue could lie with the main board. I am wandering if anyone can help me how to test this board to figure which component is the issue. The tv has no picture or sound but i get the standby and click. i have attached a picture of the board i want to test,

    thanks

    sarah
    Attached Files
  • tvtimmy
    Badcaps Legend
    • Mar 2015
    • 1160
    • usa

    #2
    Re: testing a main board

    Unplug the ldvs ribbon from the mainboard to the control board, then put a piece of wire to short out these 2 holes on the control board. Plug the tv back in and see if you get test patterns on the screen. If you do, the mainboard is bad. Probably due to bad BGA soldering under the chip.
    Attached Files

    Comment

    • sarah2010
      New Member
      • Dec 2019
      • 6
      • United Kingdom

      #3
      Re: testing a main board

      Put a bit of solder in does both end need to touch at back of control board? Didn't get test patern.

      Comment

      • diif
        Badcaps Legend
        • Feb 2014
        • 6978
        • England

        #4
        Re: testing a main board

        Originally posted by sarah2010
        Put a bit of solder in does both end need to touch at back of control board? Didn't get test patern.
        Yes, they need to touch. Forget soldering, just shove in a piece of wire stripped at both ends.

        Comment

        • sarah2010
          New Member
          • Dec 2019
          • 6
          • United Kingdom

          #5
          Re: testing a main board

          Put wire in the 2 holes twisted them together to make sure contact, no test pattern

          Comment

          • sarah2010
            New Member
            • Dec 2019
            • 6
            • United Kingdom

            #6
            Re: testing a main board

            Do you know what vaults should go to m_on and rl_on on the psu?

            Comment

            • vinceroger69
              Badcaps Legend
              • Mar 2012
              • 6714
              • uk

              #7
              Re: testing a main board

              The lg training manual in post 5 of this thread may help
              https://www.badcaps.net/forum/showth...ht=LG+60pb690v

              Comment

              • tvtimmy
                Badcaps Legend
                • Mar 2015
                • 1160
                • usa

                #8
                Re: testing a main board

                Did you unplug the ldvs ribbon cable too?

                Comment

                • sarah2010
                  New Member
                  • Dec 2019
                  • 6
                  • United Kingdom

                  #9
                  Re: testing a main board

                  The ribbon going from control board to main board, yes

                  Comment

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