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    #1

    LG Flatron Widescreen Issues

    Picked this up from one of my clients last week.. finally got around to it a couple of days ago. Unit didn't turn on at all. Opened it up and voila I found 4 bulged caps.. there was a 5th one in the group that wasn't bulged but I replaced it anyway.

    The model is L204WT-SF

    Put it back together somewhat.. well I got the thing to turn on at least but still no image on the screen, no logo either.. ** scratching head** So I checked the rest of the caps on the board one of the 50v ones read 6 on the ESR meter so that is kinda iffy and the other 50v one had no reading whatsoever.. so I know I have to replace this.

    My question is about the Schottkey diodes.. there are 2 of them on the board.. I'm not 100% sure if they are bad or not.. but I think they are... when I measured them with the OHM meter.. they read completely shorted in both directions.
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    www.bcrelectronics.ca
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    #2
    Re: LG Flatron Widescreen Issues

    Is there an image on the screen if you look with a flashlight?

    I fixed an identical board last week. It was just caps.
    I replaced ALL the caps, including the small electrolytics.

    I would check the Schottky's out of circuit, to ensure you're not measuring something in parallel to it. Remember that a Schottky will measure some conductance in the reverse direction, though shouldn't read completely shorted.
    36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

    Comment

      #3
      Re: LG Flatron Widescreen Issues

      I agree with smason that you should check the diodes out of circuit. It's hard to believe that both of the dual diode paks are shorted out.

      Comment

        #4
        Re: LG Flatron Widescreen Issues

        Originally posted by Solder Boy View Post
        ones read 6 on the ESR meter

        My question is about the Schottkey diodes. when I measured them with the OHM meter.. they read completely shorted in both directions.
        6 is high. For caps it should be around 0.6 or less I believe.

        The diodes are bad, but check out of circuit to be sure. It could be the surrounding components affecting the measurements.
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          #5
          Re: LG Flatron Widescreen Issues

          Have you checked the fuses yet?

          Comment

            #6
            Re: LG Flatron Widescreen Issues

            Thanks for the input guys! I did check the fuse.. it's good. I will replace the rest of the caps first and see what happens. I won't bother with the diodes unless replacing the caps doesn't solve it.

            It was too bright in my living room to even check for an image with a flashlight.. will provide an update when I get the replacement caps
            www.bcrelectronics.ca

            Comment

              #7
              Re: LG Flatron Widescreen Issues

              Just an update on this Flatron: I finally got it repaired and running!

              I obtained the 2 caps I needed.. soldered them in.. put everything back together somewhat.. held my breath, turned it on... and voila! It came to life picture and all.

              Woohoo! This is my first successful LCD repair. I was pretty stoked about it yesterday when I fixed it. Did a google search of the model number.. this thing was worth almost $400 back in 2007.

              Had to do some fiddling around with the controls to get the screen to look ok as it appeared to be "washed" out. Brightness, Contrast and Gamma levels were all screwy so I got that solved..

              Now I just have to get a decent video card with DV-Out to get the full benefit of this beauty!

              www.bcrelectronics.ca

              Comment

                #8
                Re: LG Flatron Widescreen Issues

                Originally posted by Solder Boy View Post
                Just an update on this Flatron: I finally got it repaired and running!

                I obtained the 2 caps I needed.. soldered them in.. put everything back together somewhat.. held my breath, turned it on... and voila! It came to life picture and all.

                Woohoo! This is my first successful LCD repair. I was pretty stoked about it yesterday when I fixed it. Did a google search of the model number.. this thing was worth almost $400 back in 2007.

                Had to do some fiddling around with the controls to get the screen to look ok as it appeared to be "washed" out. Brightness, Contrast and Gamma levels were all screwy so I got that solved..

                Now I just have to get a decent video card with DV-Out to get the full benefit of this beauty!


                Congrats, it's always nice to hear a success story!

                Comment

                  #9
                  Re: LG Flatron Widescreen Issues

                  Originally posted by Solder Boy View Post
                  I obtained the 2 caps I needed.. soldered them in.. put everything back together somewhat.. held my breath, turned it on... and voila! It came to life picture and all.
                  Another good example for newbies reading this. The 2 caps replaced were the 50V in post #1. One measured 6 ohm on the ESR and the other had no reading.

                  Both of these caps would show no visible bloating, yet they were bad.
                  --- begin sig file ---

                  If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                  We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                  Please do not post inline and offsite as they slow down the loading of pages.

                  --- end sig file ---

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