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    #1

    Used Multimeter question.

    I have a chance to buy a used Amprobe AM 510 at a really great price. The problem is that I don't know for certain how to determine if it will read current, as the re-sale store it is at doesn't want me to wire it in series to check it, or even open it to test the fuses.

    I did test for continuity with another meter, AM510 dial set at both amps, and ma, and there was continuity. Does this at least indicate that that the fuses are likely intact?

    Store says it will refund money if it is broken, but I'd feel better if I had a way to test current reading function without disassembly, or creating an impromptu series wiring. If fuse was blown, store could easily say I did it.

    Realizing it's not the best meter, but it's spotless-looks new, all other functions work, and it's priced at less than cost of single fuse. Would my other meter have any cause to show continuity if the AM510's fuses were blown? Thoughts? Thanks for any input.
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    #2
    Re: Used Multimeter question.

    When you buy used and can't open it, assume the fuse is either bad or the incorrect type.

    For example, I bought an used Fluke 87 locally and while I tested the 10A fuse without taking apart the meter, when I got home, I discovered this little surprise ...

    https://www.badcaps.net/forum/showpo...2&postcount=17

    So price in the cost of two proper fuses for this meter and if it still works out to be a good deal, then buy it.

    Alternatively, buy the meter, open it in front of the resale store people and test/check the fuses in front of them. If there is a problem, then they shouldn't have a problem refunding your money on the spot. Take this post and show them what the fuses should look like in a brand new meter.

    The fuses for the AM-510 are documented at



    The 11A fuse is the same one found in high end meters like Fluke, Keysight, Brymen, etc and normally cost between $7 and $10 each. The 500mA is likely to cost around $5.

    If you see glass fuses in the used one, you know they are not the correct type. They should look something like the pictures at

    http://www.eevblog.com/forum/reviews...nder-the-hood/
    Attached Files
    Last edited by retiredcaps; 12-08-2016, 06:08 PM.
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      #3
      Re: Used Multimeter question.

      Assuming everything is good you should be seeing

      10 amp range will be less than half an ohm (depending upon shunt design and the rest of the electronics but if you are getting a value in this area it should be good)

      The milliamps range I would expect to see a value of between 5 and 6 ohms again this will vary with the shunt value and the miliamp range it measures

      Providing you are getting values in this area the meter should be good.

      hope this helps
      Last edited by llonen; 12-08-2016, 06:21 PM.

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        #4
        Re: Used Multimeter question.

        Originally posted by llonen View Post
        Providing you are getting values in this area the meter should be good.
        As I tried to convey in post #2, you cannot go by readings alone. The AM-510 comes with HRC expensive fuses. If the used one has glass fuses, they won't meet the safety ratings on the meter and the OP will have to spend probably $15 to $20 USD to buy new HRC fuses.

        The threaded screw/bolt found in the Fluke 87 reads less than 1 ohm, but that doesn't mean it is a proper fuse.
        Last edited by retiredcaps; 12-08-2016, 06:27 PM.
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          #5
          Re: Used Multimeter question.

          Originally posted by llonen View Post
          Providing you are getting values in this area the meter should be good.
          In addition, unless you visually check, you could be getting a 10A 250V fuse when it should be 11A 1000V fuse.

          Both will measure under 1 ohms easily.
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            #6
            Re: Used Multimeter question.

            To clarify it was not the fuses I was referring to, those would still need inspecting, rather the values I was referring to were that of the meter shunts themselves, fuses are easy enough to replace, the meter shunts are much more of a problem if they have been damaged or destroyed.
            Last edited by llonen; 12-08-2016, 06:43 PM.

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              #7
              Re: Used Multimeter question.

              Weird, they were fine with buying it, and opening it there. Good suggestion, Thanks.

              One 660 V 500 mA, and one 660 V 10 A. Both checked out. They weren't ceramic that I'm used to seeing, but similar material--certainly not glass. Guessing fast blow, but all I could make out on the end caps was voltage and current ratings.

              Unlike the pictures of the fuses in the pictures of the AM520, both fuses in this AM510 were approx. the same size, with no writing on the side, just rating on end caps. Don't know if that's as it should be, or if meter is counterfeit, or some other oddity. I'll probably poke around and see if I can find a picture of an actual AM510 online to satisfy my curiosity.

              Thanks all for the input.

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