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I have not come across this issue before in searches on this forum and searches on Google. I wonder if anyone else has come across it.

My digital multimeter is unable to measure ohms. I'm just trying to read a simple single 100R resistor but the readings fluctuate.

I took the leads out and replaced, but still have the same problem.

I took out the leads completely, and the multimeter still shows a reading even when open circuit.

Can this be fixed or do I have to buy another one?

ghost resistance

Also other photos and a video at : https://i.stack.imgur.com/C41Ui.jpg

Thanks in advance for your guidance.

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    \$\begingroup\$ Check the battery, check the leads contacts (both ends), and the continutity in the middle of the leads (gentle pulling and twisting), before you bin it and buy a new one. \$\endgroup\$
    – Neil_UK
    Oct 26, 2021 at 6:07
  • \$\begingroup\$ Is it possible it got wet? \$\endgroup\$ Oct 26, 2021 at 7:51
  • \$\begingroup\$ Neil_UK Yeah I've changed the leads and then I thought of unplugging it completely (which I've done as per pic). The reading should say 1. but it is giving me a kOhm reading which shouldn't be the case. Spehro It hasn't got wet I think, unless through humidity. I have measured AC with it but I don't think it's blown or anything. I've already opened it to inspect if any solder points were obviously cracked but none of that as far as I noticed. \$\endgroup\$
    – Azrudi
    Oct 26, 2021 at 14:40

2 Answers 2

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Low or dead battery is the common cause. The internal voltage reference is not very stabile when the battery gets below a certain level (exact value depends on the exact meter used). In any case, battery is the issue about 90% of the time. Other issues can be broken test leads or poor connections in the banana jacks in the meter.

Good luck

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  • \$\begingroup\$ Thanks for the comments. All the replies seem to say the battery. I use a rechargeable battery in the multimeter, 9V Ni-MH. Do you think the rechargable battery could be the issue? I don't have a spare standard one at the moment or I would verify it now. \$\endgroup\$
    – Azrudi
    Oct 26, 2021 at 14:37
  • \$\begingroup\$ @Azrudi: You should use the type of batttery the meter is designed to use. I think an NiMH "9V" battery's maximum voltage is somewhat below 9 volts. \$\endgroup\$ Oct 26, 2021 at 16:25
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You can check the meter's battery while powering the meter.

  • Select DC volts.
  • Touch the V lead to each battery terminal in turn.
  • Subtract the readings from each other to get the total battery voltage.

This works because the COM voltage is somewhere around midway between the supply voltage.


While you have it open take the PCB out and examine and clean the multipole switch wiper contacts and gold plated PCB contacts.

enter image description here

Figure 1. The contacts arrangement will be similar to this. Image source: Engineers Garage (without any apostrophes!).

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  • \$\begingroup\$ Hi, thanks for your reply. Is the multipole switch wiper the round bits of contact when you select what mode the multimeter should go to? That's a great tip about using the multimeter itself to test its battery. The battery is newly charged, but this is a useful tip. \$\endgroup\$
    – Azrudi
    Oct 26, 2021 at 14:35
  • \$\begingroup\$ It will be something like engineersgarage.com/wp-content/uploads/2019/07/…. See the whole article here: engineersgarage.com/insight-how-digital-multimeter-works. \$\endgroup\$
    – Transistor
    Oct 26, 2021 at 14:38
  • \$\begingroup\$ Thanks, yeah I saw this part when I was opening it. I've cleaned it too but I'll clean it again. \$\endgroup\$
    – Azrudi
    Oct 26, 2021 at 14:45

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