How to test an used DMM?

Discussion in 'General Electronics Chat' started by AKnogood, Nov 27, 2013.

  1. AKnogood

    Thread Starter New Member

    Nov 21, 2013
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    I'm going to buy a used DMM (looking for a Fluke 87V) from local classified ads and would like to know if you'd have any recommendation as to how I should test it before buying it? Should I bring a basic circuit with known values along with some parts like R,C etc?

    Would you have any specific circuits to recommend? I haven't played with electronics for the last 10 years so I'm pretty rusty..
     
  2. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    I have a set of precision (.01%) resistors I use for checking Ohms cal. If you get a set of 1% resistors and have access to a very accurate meter, measure them and write the values on a piece of tape or paper. For voltages, you need a second accurate meter to piggy back on the test meter to check. For current, use a calibration meter in series with the test meter to check. Basically: to check a meter, you need a better meter.
     
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  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,388
    1,605
    What you don't want is to get stuck with a meter with a dead range.

    Bring along a battery, some resistor (1K or 10K whatever you have or get from Radio Shack) and make sure the guy has the test leads or you need to bring those too.

    You can check DC volts with the battery, AC volts with a wall outlet, resistance with the resistor, DC current with the resistor and the battery.

    That leaves out AC current... the temperature and the diode scale.

    It's quite common for people to blow the fuse inside the meter used for current measurements. It's not a bad thing but you need to replace it before checking the current ranges.

    Unless you intend to get it calibrated with traceability back to the National Bureau of Standards forget the .01 percenters.
     
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  4. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,548
    2,373
    When you first power the meter, it will show all display digit segments, sign and range labels, turn it off on a couple of times and check for any missing segments.
    Max.
     
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  5. ian field

    Distinguished Member

    Oct 27, 2012
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    784
    Its probably the current ranges most likely to have suffered abuse - closely followed by the resistance ranges.
     
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