I've got a Caltek CM1200 multimeter, which I bought ages ago. http://www.caltek.com.hk/cm1200.htm

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It can measure voltage perfectly. I'm pretty sure the battery works, as it displays 0 when you go to a voltage with nothing connected to the probes.

When I move the dial to the resistance measuring area, the display shows nothing. Completely blank (I expect something meaning infinite).

If I connect the two probes (plugged into the bottom two sockets, marked V/Ohm/mA and COM) to each other, it is still blank (I expect zero).

What is wrong with my multimeter, or am I missing something at how to measure resistance?


2 Answers 2


I suspect an internal failure of the meter, which most likely means replace.

  • \$\begingroup\$ The failure could likely be a reparable fuse. The terminals used to measure current on multimeters usually have fuses to protect them from excessive current, and it looks like this meter measures small currents (mA) on the same terminal as resistance. \$\endgroup\$
    – Phil Frost
    Jan 28, 2013 at 19:57
  • \$\begingroup\$ @PhilFrost I would suspect that except it measures voltage, just not resistance. It never hurts to check a fuse though. \$\endgroup\$ Jan 28, 2013 at 20:43
  • \$\begingroup\$ Most multimeters i've encountered only have user-replacable fuses for current measurement (and even then often only for the low-current input, not the high current input), not for the voltage or resistance ranges. \$\endgroup\$ Sep 15 at 21:10

Check that there isn't a separate battery for resistance measurements. I actually have a old meter like that. There are a few AA batteries for running the electronics, and everything except the resitance scales work fine. There is a single D cell for providing the current for resistance measurements. The resistance scales are flaky when that gets low, and it isn't tested in the battery test mode.

I don't know if your meter is like this, but it's something to check.


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