DIYbanter - View Single Post - Extech DC clamp meter, large DC offset developed.

M Philbrook

In article , says...

On 14/07/2016 03:34, M Philbrook wrote:

Just got a Extech 845 , 1000 amp AC/DC clamp with a basic DMM on it and
IR..

I used the DC amp once, it worked.. put the meter away, next day used
it again. As soon as I select DC amps now, it shows a -32 Amp offset.

I can zero it however, It looks like the value its reporting is ~
50% of the actual value.

I have not used this meter for nothing else yet, but I did plug in the
test leads to check to make sure the rest of the meter worked after
seeing this, and it seems to work ok on the other funtions..

Is anyone familiar with this failure ? The initial offset was only
about +/- 0.5 amps if I remember..

Jamie

I would get inside and clean any range/function switch contacts.
Does the manual advice against use near loudspeakers, laying meter jaws
next to screwdrivers etc

this meter is only a few days old in my hands, there should be no crud
in there.

The manual only says to remove test leads when using the clamp and
there is an obvious reason for that, to prevent the leads getting into
the equipment while reaching in. The leads were still in the package.

I will try a demagnetizer/degaussing process

Jamie