UT210E clamp meter amps measurements wrong

[marce002]

Hello all

I have an UT210E clamp meter that went wrong doing amps measurements in continuity DC, it shows an offset of around 4/5A when first set, (lever at DC 10A) at 2A DC shows fixed 0L always......,,,,,, and also does not allow me to (zero button) , and as i said it is even worse in the 2A !! setting which do nothing and shows "0L"... when you can measure DV in 20A after achiving a ZERO with many RESET ZERO times , you can measure with a lot of offset..... eg 1A current is measured at around 650 mamps, . Similarly, a 4A current is shown at around 3A. |O

What can be wrong?

video with the issue: https://youtu.be/Wrffkx4lpA0


What is wrong with this clamp? I have a ut210E nice for small DC measurements. One day stopped working... 2A shows always OL and in 20A shows an offset of 5A!!! Until reset several time I can get 0amps but measure is wrong

[clearchris]

Re: UT210E clamp meter amps measurements wrong

Your red probe doesn't look like it's pushed all the way in. Check the plugs, make sure there's nothing in there, etc. Recently, I had to take apart my meter, clean up the insides and resolder the banana jacks. Your meter doesn't look particulary new either. Otherwise, not sure.

[stj]

Re: UT210E clamp meter amps measurements wrong

did you use it for high current like car starter motor??

[budm]

Re: UT210E clamp meter amps measurements wrong

Did you open it up and inspect the board?

[stj]

Re: UT210E clamp meter amps measurements wrong

Your red probe doesn't look like it's pushed all the way in. Check the plugs, make sure there's nothing in there, etc. Recently, I had to take apart my meter, clean up the insides and resolder the banana jacks. Your meter doesn't look particulary new either. Otherwise, not sure.

it does not use the probes, it has a hall-effect sensor in the clamp

[redwire]

Re: UT210E clamp meter amps measurements wrong

First check if the iron jaws are magnetized, they probably need degaussing.

Small chance the Hall sensors offset/cal has gone bad. There are three trimpots on the main board VR+, VR-, VR4 but I'm not sure which one is Hall offset. There are two sensors and you would have to measure voltages to troubleshoot.

Found this UT210E schematic which shows them.
OP crossposted here: https://www.eevblog.com/forum/testge...sg3058496/#new

[marce002]

Re: UT210E clamp meter amps measurements wrong

Thanks a lot redwire... did not measure nothing strange at all .. only low current apps in rc models most of the time at 2a.... First check if the iron jaws are magnetized, they probably need degaussing... but how can i check iron jaws for magnetizement?
I would like to never have to touch the inside trimpots..

[redwire]

Re: UT210E clamp meter amps measurements wrong

You can accidentally magnetize the jaws just going close to a magnet, your RC motors could do it if you bumped a motor.
Take a small steel screw or nut or washer (that is not magnetized at all) and see if it "sticks" to the jaws. That can show if they are magnetized.
You need an AC field or current (not a magnet) to fix, and to fade out to zero. I use a cassette or bulk eraser or CRT TV demagnetizing coil.
It could also be done wrapping many turns of wire in the jaws and pass AC current (so the turns*amps= ~100 for say a bad 100A offset).

Then I run AC current (meter is off) and then slowly open the jaws and pull them away, so the AC field is slowly reduced to zero. A series PTC thermistor could work too.
I wouldn't touch the trimpots either, until you know the jaws and hall sensors are OK.

[marce002]

Re: UT210E clamp meter amps measurements wrong

thanks redwire, you are the kind of person that make a forum interesting..... i will try to do something of this and will coment soon. my offset is 5A dc , so if any idea of #turns (in a say 2cm diameter core cilinder) and maybe
use coaxial tv cable (internal copper with its cover)... the only power supply that i have is a 220v to 12v 5a AC from a car battery charger

[budm]

Re: UT210E clamp meter amps measurements wrong

"I have an UT210E clamp meter that went wrong doing amps measurements in continuity DC"
I guess I read it wrong, I thought OP has the meter in Continuity mode and use the probes to test the current.

[Garbologist]

marce002 did you ever figure this out? Mine is doing the exact same thing and after probing it with the aid of the circuit diagram linked in the post above, I think maybe the op-amp chip may be bad. It’s a 4 op-amp chip which appears to be a Chinese copy of the OPA4330, and is configured as an instrument amp for the current probe.

[sam_sam_sam]

I also had a dc clamp meter and it would not read correctly after a couple of years of use so just never got a replacement for it but if I were to get a replacement one what brand is is a good one that would not require an arm and a leg to buy i

[Garbologist]

There is a write up on repairing this issue over on the EEVblog forum: https://www.eevblog.com/forum/repair...re-and-repair/