WESTINGHOUSE EW24T7EW - no backlight

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  • jasonbay13
    Senior Member
    • Jul 2014
    • 185
    • usa
    #1

    WESTINGHOUSE EW24T7EW - no backlight

    i have a WESTINGHOUSE EW24T7EW with inverter board MP113S-39.
    looks almost exactly like this: http://www.shopjimmy.com/media/catal...13s-39-top.jpg

    i did a thorough look through to see if any caps were even slightly bulged or any melt marks anywhere, but found nothing out of the ordinary.

    i can faintly see the westinghouse logo when i turn the tv on so i checked the voltage at the backlight plug con5 and got 6 volts receeding to 0.
    so i applied 18v to the backlight and turned the tv on, the logo appeared (not full bright, but enough to see clearly)

    is there anything i can do to revive the board? or just find one for like 20-30$


    thanks, me
    Tags: None
    • jasonbay13
      Senior Member
      • Jul 2014
      • 185
      • usa
      #2
      Re: WESTINGHOUSE EW24T7EW - no backlight

      forgot to mention that the tv had this problem, but i put the tv away for a while, decided to try it again before digging into it and it suddenly decided to start working and did work for months.

        Comment

        • bammbammfran
          Badcaps Veteran
          • Apr 2014
          • 476
          • USA
          #3
          Re: WESTINGHOUSE EW24T7EW - no backlight

          why did you run 18 volts to the inverter when it looks like it is only supposed to use 12 ?
          Where do con 4 and con 5 lead to and do they have voltage and is that voltage steady?

            Comment

            • jasonbay13
              Senior Member
              • Jul 2014
              • 185
              • usa
              #4
              Re: WESTINGHOUSE EW24T7EW - no backlight

              i started at 3 volts and kept going up until i saw something at 18. so i would assume its 24volt.
              and i dont know where con4 and con5 lead to. i could get a clear picture of both front and back if it would help. but it looks like they are in series and one side goes to ground? and the other side goes through a bunch of little resistors?
              i'll check for voltage further down the line when i get to it.

                Comment

                • bammbammfran
                  Badcaps Veteran
                  • Apr 2014
                  • 476
                  • USA
                  #5
                  Re: WESTINGHOUSE EW24T7EW - no backlight

                  Well, I found a bottom picture of the board and it says 12volts on two of the pins at con2
                  then it also looks like this may feed a voltage regulator at Q11 which might be 5 volts to those two connectors ??? If those two connectors do not lead anywhere then that voltage may just be a feedback current to the one 8 pin IC at IC2
                  check voltages with the board all by itself and then again with it connected to the main board

                    Comment

                    • jasonbay13
                      Senior Member
                      • Jul 2014
                      • 185
                      • usa
                      #6
                      Re: WESTINGHOUSE EW24T7EW - no backlight

                      ok, i did some testing. and i shorted +12 to bk/on with my black lead and put the red lead to various places. (first at the terminals on connector 4 and 5). at con5 i get -11.8v and at con4 i get 48v quickly dropping to 0, but goes back to 48 everytime i re-short +12 and bk/on.

                      i get 11.8v everywhere i checked except the section with con4, and down to the resistor? with 3903 (R27) on it, but the other side of the resistor has 11.8?

                      i can draw up an image if you want me to of where i checked voltages/where you want me to check voltages.
                      Last edited by jasonbay13; 07-06-2014, 12:01 PM.

                        Comment

                        • bammbammfran
                          Badcaps Veteran
                          • Apr 2014
                          • 476
                          • USA
                          #7
                          Re: WESTINGHOUSE EW24T7EW - no backlight

                          Sorry, but, I can't play by your rules

                            Comment

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