I have a multimeter that I haven't used in many years. I wanted to recalibrate it, so I touched the two probes and tried to adjust the reading to zero, but 500 ohms was as low as it would go. Is the meter bad?

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    500 ohms is a pretty huge reading. Thats not even close. Can the leads be replaced or are they hardwired? Are the leads clean? Is it a digital meter?
    – JPhi1618
    Oct 31 '17 at 13:34
  • Clean leads, analog meter. I updated the question to be more specific. Oct 31 '17 at 19:45

I assume, since it has a zero-ohms adjustment at all, that this is an analog multimeter (one with a physical moving needle). In which case, you should try replacing the internal batteries. They are used only in resistance mode (so everything else will work), and if they are weak they will not be able to produce enough current to move the needle to full scale, which is what you are seeing.

Many meters do not have separate battery compartment doors. If you do not see one, try removing the entire back cover (if there are obvious screws with which to do so). You may also find fuses, which would need to be replaced if the current mode of the meter is not working.

The above advice is for the zero ohms point which is at the far-right end of the scale. The left-end zero in other modes — where the needle rests when no connection is made — should be adjusted using the screw or knob on the face of the meter at the pivot point of the needle. This is a mechanical adjustment of the return spring. If turning it has no effect, then the meter may be damaged, or the linkage between the adjustment screw and internal parts may have become disconnected in which case careful disassembly and reassembly may fix it.

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    There was no little externally accessible battery compartment, so I didn't even think of taking out the screw and looking inside! That was exactly the issue. Oct 31 '17 at 13:58
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    @ScottCWilson Oh, that is a good thing to mention too, thanks, edited.
    – Kevin Reid
    Oct 31 '17 at 14:07
  • Mine have same problem, even if fresh new batteries. Needle just move a little and cannot zero in. How to diagnose?
    – eigenfield
    May 25 '21 at 6:37
  • @eigenfield Comments on an old answer aren't a good place to ask questions because very few people will see them and they aren't meant for that. Please post a new question which includes what you've tried so far and photos of your meter's face and inside. It might also be best to post it on the Electrical Engineering site since it's less about home improvement and possibly less simple than the problem this original question was.
    – Kevin Reid
    May 25 '21 at 15:16

Analog meters can get knocked out of whack from being banged around or a modest drop. It may need a trip to the repair shop. A cost conscious move might dictate a replacement is in order.

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    Many times if the movement won't zero with fresh batteries the movement screw on the face of the meter can be adjusted prior to a complete replacement.
    – Ed Beal
    Oct 31 '17 at 14:52

+1 on internal batteries. I always use top quality batteries so hey dont leak, i always label or mark the back as well as batteries the replacement date. i it has been a few years you are at risk. Remove if shelving the meter.

I frequently use my 30+ year old taut-band analog meter as it's very easy to tracking changing values vs on a digital where the lower digits are just a blur.

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    Without getting into exactly how old the battery was, let's just say the maker was "Tandy Corp." and the battery was original. :( Oct 31 '17 at 17:14
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    This is no different than @KevinReid's answer. Rather than writing a separate answer to simply say you agree with another answer, the correct method is to vote up the other answer.
    – mmathis
    Oct 31 '17 at 18:50
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    @ScottCWilson I'm amazed it didn't leak decades ago... Oct 31 '17 at 19:34
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    some digital meters have a analog-esque bar on the bottom, which updates faster than the digits, and allows visual comparison between say 2.99 and 3.01.
    – dandavis
    Oct 31 '17 at 23:07
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    @ScottCWilson I have a Casio FX-100D calculator on my desk which I bought sometime at uni, which makes it 1997 at the latest. It was used daily at uni, and since then has tended to get used fairly regularly at work as well. The batteries finally ran out earlier this year. They don't make them like they used to! :)
    – Graham
    Nov 1 '17 at 11:52

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