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Dell E171FP, GH15/17/18, No power

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    Dell E171FP, GH15/17/18, No power

    I'm troubleshooting this Dell E171FP display that has no signs of life whatsoever.

    I've pulled the power board out of the screen and have tested the fuses as good (in-circuit) and I have 120-volt power at the input pins of the D2SBA Bridge Rectifier but 0 volts on the output pins.

    I'm fairly inexperienced at component level testing. Will I have output voltage at these pins with nothing at all connected to this power board except the 120-volt input?

    I do not even see a standby light but I wanted to make sure this board isn't waiting for some sort of "turn on" signal or something.

    I didn't even see a standby light so this zero volts leads me to suspect this rectifier is faulty.

    Thanks in advance.

    #2
    Re: Dell E171FP, GH15/17/18, No power

    probaby bad capacitors given the age of those.

    Comment


      #3
      Re: Dell E171FP, GH15/17/18, No power

      Originally posted by stj View Post
      probaby bad capacitors given the age of those.
      I might add, this unit has been sitting not functioning for a very long time.

      I decided to give fixing it a shot and I figured it's already broken so I cannot make it worse.

      You are thinking the bigger ones?

      C14 - C19? There is a much bigger fella too. C5

      Comment


        #4
        Re: Dell E171FP, GH15/17/18, No power

        i'm thinking the smaller ones first - they dry out faster.
        also, the small ones are responsible for starting the psu, the medium size ones are just to keep it stable afterwards.

        Comment


          #5
          Re: Dell E171FP, GH15/17/18, No power

          Show us the pictures, using 'Go Advanced', so we can see what we are dealing with, there are many versions of this model.
          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


            #6
            Re: Dell E171FP, GH15/17/18, No power

            Sorry about that.

            Here is the photo.
            Attached Files

            Comment


              #7
              Re: Dell E171FP, GH15/17/18, No power

              that could be the cleanest board i'v ever seen!

              Comment


                #8
                Re: Dell E171FP, GH15/17/18, No power

                Originally posted by glen4cindy View Post
                Sorry about that.

                Here is the photo.
                Please provide the bottom side of the board too, thanks.
                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


                  #9
                  Re: Dell E171FP, GH15/17/18, No power

                  So here is another twist. There are some crazy things happening with this board.

                  I was doing some more probing. I was hunting for possible filtering caps or something so I followed the entire input section probing the in and out at each inductor all the way to the bridge rectifier. I had A/C about 121 volts at all points. At this point, I suddenly had about 161 volts DC at the output of the bridge rectifier and input of the large filter capacitor. I also measured around 5 volts DC at JP3 pins 6 and 7.

                  At this point, I connected the display and rest of the boards but it still had no power.

                  When I probed twice more after disconnecting everything. The first time there were 0 volts at the bridge rectifier but about 120 volts up to it. The next time I probed it the meter registered OL and beeped.

                  Comment

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