Author Topic: Multimeter Problem or User Error?  (Read 190 times)

Offline Ron M

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Multimeter Problem or User Error?
« on: February 09, 2021, 12:02:45 AM »
Yesterday I was making a 200PPM cell of Colloidal Silver when my multimeter, which I’d wired in-series to the anode as per cfnisbet’s excellent instructions and pic elsewhere on the forum, suddenly went from showing a constantly varying mAmp current (as it should) to displaying a big fat, still ‘0000’.

I switched the meter from 20m to 200m just to see if it would spring back to life and when it didn’t I opened up the multimeter and checked the battery and found a single (internal) fuse, which seemed intact.  No repair affected.  Because it was quite an old multimeter (that my dad had given me), I wrote it off and bought a replacement today. 

Thing is, during its very first run, a 500ml properly set-up cell in which I was intending to create c. 200PPM, the very same thing happened again.   About eight or so minutes into the process I was checking the electrodes and was making a very slight adjustment of the cathode and once again the lively ever-changing mAmp display became a fixed, lifeless, corpse-like ‘0000’ again.

What happened?  Please bear in mind that other than as a tool for Colloidal Silver generation, I have no experience of using a multimeter and so might have done something very basic wrong.  Have I inadvertently (no, stupidly) shortened the circuit and blown a fuse, or broken the multimeter?  If so, is it repairable or am I becoming another one of irresponsible consumerism’s useful idiots?   What’s really confusing me is that up until two days ago I’d been using the original multimeter successfully without issue in every run of Colloidal Silver I’d attempted (and was travelling from Tony Pantalleresco Colloidal Silver roughness to beautifully clear, well-formed nanoparticles, thank you Kephra et al).

I hope somebody can help me see what I’m doing wrong and help me understand why this problem is happening with me, because at the moment my foggy brain has no idea.  Thanks in anticipation.   

Offline ZeroLabs

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Re: Multimeter Problem or User Error?
« Reply #1 on: February 09, 2021, 12:39:03 AM »
The whole thing is a series circuit, links in a chain. It only takes one broken link to break the whole chain. If it's not the multi-meter, it's losing connection somewhere else along the chain.

Offline Gene

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Re: Multimeter Problem or User Error?
« Reply #2 on: February 09, 2021, 08:29:37 PM »
First off, hook it to the output and ground of your current limiter and see if that reads OK.  If yes, its not the meter and something else which would generally point to a connection issue of some kind. If no, it is the meter (or your current limiter) and then you have to figure out whats going on.  In this case, check the probes, check the battery (it could be weak and recovers and runs for a while then drains enough to cause issues - I've seen this with batteries in the past, especially with something like a multimeter which drains them VERY slowly).  If its got a turn knob to select range (a lot of newer ones are auto-ranging), give it a couple full turns back and forth to see if its just a dirty contact.  Thats a rotary switch in there with many positions.

If you need a new one (or a backup which is always a good idea), you can buy a suitable meter even from Harbor Freight or other places for $10-20 these days.  No need to go fancy.  As long as it reads milliamps to 2 decimal places, you're good.

When you do figure it out, please do let us know what it was.

Offline chrisflhtc

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Re: Multimeter Problem or User Error?
« Reply #3 on: February 11, 2021, 06:07:52 PM »
check the fuse ;) in ampere mode there are two fuses
Chris

Offline Gene

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Re: Multimeter Problem or User Error?
« Reply #4 on: February 11, 2021, 07:13:46 PM »
Not always.  A lot of older DVMM's only had one fuse and usually came with a spare fuse fitted inside the back cover.

But if a fuse is open, just a simple resistance check (pop it out) should function properly since only the current path is usually fused.  If it reads open or anything more than a fraction of an Ohm, something ain't right with it.

Offline bm777

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Re: Multimeter Problem or User Error?
« Reply #5 on: February 16, 2021, 02:38:51 AM »
I had to wire my multi-meter this way as depicted in the picture attached...

Offline ZeroLabs

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Re: Multimeter Problem or User Error?
« Reply #6 on: February 20, 2021, 07:57:56 PM »
The dedicated 10A range input terminal has a resistance wire shunt and are generally unfused. You will not get accurate low mA readings using that input. The lower amp ranges are always fused. The fuse is internal. You must open the case to get to it. Sometimes they're soldered to the pc board. Other times they're clipped in. I'm 99.999% certain yours is blown and needs replacement. They're usually fused at no more than 500mA.

Offline imcool

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Re: Multimeter Problem or User Error?
« Reply #7 on: Yesterday at 11:33:59 PM »
multimeter has 2 fuses
Fuse 1 is for low amps like milliamps
Fuse 2 is for high amps count.
You have probably burnt low milliamps fuse.