Sharp 40LE550U strange Backlight issue

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  • Jtroutt19
    Senior Member
    • Aug 2011
    • 164
    #1

    Sharp 40LE550U strange Backlight issue

    So originally though I had some bad solder joints on the backlight strips in this tv. But after tearing it down and testing them I found out that wasn't the issue. So After I got it all back together and started cleaning the Panel the backlight popped on. I took my hand off the screen and it went out.


    I quickly discovered that if I pushed on the top of the TV the backlight would come on. So what in the world is going on here. I can see the PS board flex as I push the top of the TV. I have inspected the solder joints under microscope and don't see any cracks or damage anywhere. Any ideas?
    Tags: None
    • heavymachines
      Badcaps Legend
      • Mar 2011
      • 1028
      • United States
      #2
      Re: Sharp 40LE550U strange Backlight issue

      My first thought would be wires going to led strips grounding out or cold soldier joints on boards or connectors not seating right.

        Comment

        • Jtroutt19
          Senior Member
          • Aug 2011
          • 164
          #3
          Re: Sharp 40LE550U strange Backlight issue

          I tested each individual LED strip. no bad solder joints. I will check wires thank you.

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA
              #4
              Re: Sharp 40LE550U strange Backlight issue

              Do the LED use SMD connectors to link the LED strip together? Those connectors are common failure.
              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

                • Jtroutt19
                  Senior Member
                  • Aug 2011
                  • 164
                  #5
                  Re: Sharp 40LE550U strange Backlight issue

                  I would assume it is an SMD connector. THey are super tiny and don't really hold the strips together. I am going to take the panel out of it again and push on the connectors to see if I can get the backlight to come on.

                    Comment

                    • dick_barton
                      Badcaps Legend
                      • Aug 2015
                      • 6643
                      • Wales
                      #6
                      Re: Sharp 40LE550U strange Backlight issue

                      If you suspect the connectors you can bridge across them by soldering a wire across each.
                      Willing to help but I'm no expert.

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA
                          #7
                          Re: Sharp 40LE550U strange Backlight issue

                          https://www.badcaps.net/forum/showth...124#post690124
                          Same model I worked on a while back so probably same failure.
                          Last edited by budm; 10-12-2017, 11:14 AM.
                          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

                            • Jtroutt19
                              Senior Member
                              • Aug 2011
                              • 164
                              #8
                              Re: Sharp 40LE550U strange Backlight issue

                              Yip it’s working fully now. I actually discovered that thread yesterday

                                Comment

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