Panasonic TX-48CX400B Only backlight no picture

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  • Fixing222
    Senior Member
    • May 2017
    • 67
    • --

    #1

    Panasonic TX-48CX400B Only backlight no picture

    Sound works and screen is illuminated the back light but no picture.

    The blink code when i turn on is 14 or 15 i think it is one of them im not sure
  • nomoresonys
    Badcaps Legend
    • Jan 2013
    • 12081
    • U.S.

    #2
    Re: Panasonic TX-48CX400B Only backlight no picture

    Test connector from mainboard to powerboard on powerboard side with all boards hooked up, test with tv plugged in but off then hit power, report both conditions here, give pin number, pin description/name and condition both off and when you hit power on. So we can see all the voltages and what they are doing. example in second link below if needed.

    Comment

    • Fixing222
      Senior Member
      • May 2017
      • 67
      • --

      #3
      Re: Panasonic TX-48CX400B Only backlight no picture

      Originally posted by nomoresonys
      Test connector from mainboard to powerboard on powerboard side with all boards hooked up, test with tv plugged in but off then hit power, report both conditions here, give pin number, pin description/name and condition both off and when you hit power on. So we can see all the voltages and what they are doing. example in second link below if needed.


      So it was from top of tv way to bottom
      11.98
      0
      0
      0
      1
      0

      TV ON
      11
      0
      2.6
      3.2
      0
      24.94
      I'm not sure what you mean by pin number
      Attached Files
      Last edited by Fixing222; 08-04-2019, 06:10 PM.

      Comment

      • nomoresonys
        Badcaps Legend
        • Jan 2013
        • 12081
        • U.S.

        #4
        Re: Panasonic TX-48CX400B Only backlight no picture

        Ok, I see you have one of those vestel powerboards, a lot of them don't seem to have the voltages marked on them, I better let one of the vestel pros help you. We don't see to many of those on this side of the pond.

        Comment

        • Fixing222
          Senior Member
          • May 2017
          • 67
          • --

          #5
          Re: Panasonic TX-48CX400B Only backlight no picture

          Originally posted by nomoresonys
          Ok, I see you have one of those vestel powerboards, a lot of them don't seem to have the voltages marked on them, I better let one of the vestel pros help you. We don't see to many of those on this side of the pond.
          Ok yeah it's not so pretty as others inside and not so easy hopefully incase it mattets to anyone I typed the board in and the part cn4 and got this
          Image attaches
          And the service manual/circuit diagram attached
          Attached Files
          Last edited by Fixing222; 08-05-2019, 01:12 AM.

          Comment

          • diif
            Badcaps Legend
            • Feb 2014
            • 6978
            • England

            #6
            Re: Panasonic TX-48CX400B Only backlight no picture

            Please stop posting pictures inline. Press Go Advanced then use the paper clip icon.

            Comment

            • Fixing222
              Senior Member
              • May 2017
              • 67
              • --

              #7
              Re: Panasonic TX-48CX400B Only backlight no picture

              Originally posted by diif
              Please stop posting pictures inline. Press Go Advanced then use the paper clip icon.
              Ok thanks for notifying me will do , yes take up lots of space sorry

              Comment

              • Fixing222
                Senior Member
                • May 2017
                • 67
                • --

                #8
                Re: Panasonic TX-48CX400B Only backlight no picture

                After changing T-von and mainbiard it was none of them so maybe powerboard

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA

                  #9
                  Re: Panasonic TX-48CX400B Only backlight no picture

                  Did you already try having ribbon cable between LCD panel and the T-CON board connected one at a time to see what you will get on the screen?
                  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

                  • Fixing222
                    Senior Member
                    • May 2017
                    • 67
                    • --

                    #10
                    Re: Panasonic TX-48CX400B Only backlight no picture

                    Originally posted by budm
                    Did you already try having ribbon cable between LCD panel and the T-CON board connected one at a time to see what you will get on the screen?
                    Sorry not had much time to open it up but just got round to it, same thing. That was a good idea so this rules out the two tab boards (Driver boards) attached to the LCD if no display or could it still cause no display or a short just wondering
                    Last edited by Fixing222; 08-11-2019, 05:24 PM.

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #11
                      Re: Panasonic TX-48CX400B Only backlight no picture

                      Checking Voltages on T-CON board test points will be next, I.E. VDD, VGH, VGL, etc.
                      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

                      • Fixing222
                        Senior Member
                        • May 2017
                        • 67
                        • --

                        #12
                        Re: Panasonic TX-48CX400B Only backlight no picture

                        Only have VCC multiple times but will check all of those.
                        Attached Files

                        Comment

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