[volt-nuts] Keithley 2001 - do you need to open it to calibrate it?

[Todd Micallef]

You can run the self-tests to confirm the seller was telling the truth.
Smells are probably bad caps, and if you don't feel like dealing with a
recap, returning it would be best.

The keypad is held in place using two plastic strips. If one has broken or
fallen off, then you would see the keys push away from the panel. They are
easy to fix and are sometimes glued in place.

I am guessing it was opened and promptly put up for sale. I have repaired a
couple and they are great meters, but I am hesitant to go down that road
again. You never know how damaged they could be until you strip it down.



On Sun, Jun 26, 2016 at 5:29 PM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby at kirkbymicrowave.co.uk> wrote:

> On 26 June 2016 at 20:46, Todd Micallef <tmicallef at gmail.com> wrote:
>
> > David,
> >
> > I have found that many sellers like to remove any calibration stickers or
> > tamper evident stickers. Not sure why they do that as a sticker does not
> > mean the item is calibrated.
> >
>
> The sticker on the front has been removed, but the one underdeath, which
> covers a screw, is still there, but the screw has clearly been undone, so
> the seal is "broken". I'm interested to know if it is necessary to undo the
> case to calibrate the 2001, or whether it can all be done from the front
> panel, probably removing that sticker on the front.
>
> There are a few things I am not happy about this - the front panel appear
> to move far more than I would expect. Depressing one key seems to make
> several keys nearby go retreat towards the back of the unit, although it
> appears to function.
>
> I was a bit surprised when I put it on the 2 A range, with no leads
> connected, the current is showing as high as 6 mA at times. This seems odd
> given the current is obviously zero. I realize leaving the leads open on
> voltage is going to lead to undefined results, but I would have expected on
> current for the meter to read very close to zero.
>
> If I put it on "auto", on DC current, with no leads, the reading is going
> as high as 20 nA - there's noise on the last 3 digits. I don't know if that
> makes any sense. The update rate is very fast, so perhaps that's to be
> expected unless one increases the integration time.
>
> But there are a few things making me think this meter might have issues. A
> rather strange smell was initially evident, but that seems to have cleared.
> The movement of the keys seems very odd. I will almost certainly return
> this.
>
>
> >
> > If you have 14 days, run it through the paces and perform self-tests.
> There
> > are some test scripts here https://xdevs.com/article/dmm_noise/ to see
> if
> > the meter is measuring close to others.
> >
>
> Thanks, I will take a look.
>
> My computer that has the GPIB board in is is rather sick at the minute. I
> need to sort out what is wrong with it, as its the only convenient computer
> to have a controller card in.
>
> Dave
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