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    Viewsonic LCD F200 Fuse

    LCD Viewsonic Fuse F200 (marked 3).
    I was testing this fuse for continuity and it would go from closed to open in about 1 second. I'm thinking the fuse is open (bad) but there's a short somewhere on the board.
    Does this make sense?
    Just taking a guess, I'm learning as I go.
    I've got lots of great info from the members of this forum.
    Thanks

    #2
    Re: Viewsonic LCD F200 Fuse

    If the resistance reading is around 0.3 ohm, you have a good fuse.

    Check the components like transistors for shorts.

    Originally posted by Akaister
    LCD Viewsonic Fuse F200 (marked 3).
    I was testing this fuse for continuity and it would go from closed to open in about 1 second. I'm thinking the fuse is open (bad) but there's a short somewhere on the board.
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      #3
      Re: Viewsonic LCD F200 Fuse

      I'm guessing that when you said "Closed" you meant short. In this case, there is no way a fuse would read good and then read open and then be considered good. Please post a picture of what you are measuring and put the meter on ohms - not continuity and report back what the measurement is. Sometimes continuity meters will beep for a second if there is a bad fuse and it is reading through other components in the circuit. If there is any way of removing this fuse and reading it out of circuit, I'd recommend that over anything, however, this isnt always the case.
      The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

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        #4
        Re: Viewsonic LCD F200 Fuse

        Good point. Depending on the DMM, using beep continuity mode on a fuse may not be all that accurate. Some DMM report continuity if it is less than 30 ohms.

        I tested a picofuse that had 17 ohms and the continuity test beeped. However, the backlight would not come on. After I replaced the picofuse it read 0.3 ohms and the monitor worked.

        Originally posted by Dgtech
        Please post a picture of what you are measuring and put the meter on ohms - not continuity and report back what the measurement is.
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        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.

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          #5
          Re: Viewsonic LCD F200 Fuse

          The F200 is the fuse on the Viewsonic LCD that is known to blow. I referred to open as in infinite, no continuity, blown fuse.
          Ran the test again and got no reading, infinite, open. I reversed the probes and got 18 ohms for a few seconds and then it went infinite.
          I'm going to replace the fuse and see what flies. And I will definitely test it again when removed. I have to wait for the fuse because I didn't know about the F200. I read a post that someone closed that fuse with solder but I'm not that daring.
          It had some bad Capxon caps so I replaced all 9 with Panasonics. Replaced the two AOP605 Mosfets.
          I can see the monitor display but no backlight.
          This is my first monitor repair, much to learn.
          This forum is tops
          Thanks for your help

          Comment


            #6
            Re: Viewsonic LCD F200 Fuse

            Since we know for sure now that this fuse has indeed blown open due to increased current (by definition), it is usually common practice to identify which part caused the failure. This component would usually measure low in the ohms resistance readings. This may have been a part that you already have changed. If the defective shorted component has not been changed, this F200 will blow again.

            I'm curious, did you take those measurements with the new components or the old? If old, I'd retake the measurements now to compare the differences.
            The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS

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              #7
              Re: Viewsonic LCD F200 Fuse

              I replaced the F200 fuse with a 4 amp glass type. Everything works, what a nice feeling when that monitor comes back to life.
              I saw another forum member (Kozimus) had done this fuse mod.
              Thanks for the help, I'll be back. I know I had some beginners luck.
              Attached Files

              Comment


                #8
                Re: Viewsonic LCD F200 Fuse

                Originally posted by Akaister
                The F200 is the fuse on the Viewsonic LCD that is known to blow. I referred to open as in infinite, no continuity, blown fuse.
                Ran the test again and got no reading, infinite, open. I reversed the probes and got 18 ohms for a few seconds and then it went infinite.
                When you reverse the leads, some capacitors get charged up and then you see infinity again.

                I would have used the mini fuse instead of the regular sized fuse. But, as you have proved to us; whatever works. Good job!

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