Hitachi L40C205 lines in display after Backlight Inverter Repair

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  • fharris1977
    Senior Member
    • May 2017
    • 132
    • United States
    #1

    Hitachi L40C205 lines in display after Backlight Inverter Repair

    Hello. I replaced the backlight inverter on this set for a customer and there are lines horizontally and vertically on the display. They show up sometimes I guess depending on the color of the background screen (will include pictures). The customer swears the lines weren't in the screen before the backlight inverter went out. I thought it may be a bad T-con board at first but this set has no T-con board. So if anyone can help, do you think my problem is in the mainboard, the backlight inverter I replaced, the power supply, a cable, or the display (which means the customer is lying or just didn't notice it). What do you think? Thanks in advance.
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    • petehall347
      Badcaps Legend
      • Jan 2015
      • 4427
      • United Kingdom
      #2
      Re: Hitachi L40C205 lines in display after Backlight Inverter Repair

      what is it like with a tv picture ?

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA
          #3
          Re: Hitachi L40C205 lines in display after Backlight Inverter Repair

          I am having a hard time seeing the symptom on those screen shots.
          For example like this one: https://www.badcaps.net/forum/attach...3&d=1596227528
          The LCD panel has integrated T-CON board so T-CON board is not replaceable.
          Did you try re-seating the LVDS cable?
          Did you try tighten all the board mounting screws?
          Did you try heating/cooling the main board?
          If it is the panel/T-con issue, you will have to get to the Tab bonding/T-con board and try heating and cooling and some pressing probe on that Tab bonding/T-con board.
          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

            • fharris1977
              Senior Member
              • May 2017
              • 132
              • United States
              #4
              Re: Hitachi L40C205 lines in display after Backlight Inverter Repair

              Originally posted by petehall347
              what is it like with a tv picture ?
              Hi. These are photos of it with a ps4 attached. The vertical lines in the HDMI box has now vanished after reseating the lvds connector to the tab board. The vertical lines are affected when I push in on the lvds connector. Don't know if its because of movement of the board causing tabs to move or connector or cable itself. The horizontal lines don't ever go away. I think the vertical lines are panel/tab related and the horizontal lines are caused by another issue. What do you think? I've included more pics of what I'm talking about.
              Attached Files

                Comment

                • budwich
                  Badcaps Legend
                  • Jul 2015
                  • 3097
                  • Canada
                  #5
                  Re: Hitachi L40C205 lines in display after Backlight Inverter Repair

                  someone did a "hand job" on the cabling with a made up cable as opposed to the normal ribbon cable. As a result, this could cause a "timing / impedance" problem with signals to the panel which you are likely seeing.

                    Comment

                    • fharris1977
                      Senior Member
                      • May 2017
                      • 132
                      • United States
                      #6
                      Re: Hitachi L40C205 lines in display after Backlight Inverter Repair

                      I think is the original cable. Just an older LCD set.
                      Attached Files

                        Comment

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