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

[Tom Knox]

Hi All;

One thing to check for 0n the 2001 is leakage on the electrolytic caps. Especially the early ones (Identifiable by the finer mesh fan filter) commonly have this problem and if unattended the oil eats the traces making repair a real nightmare.

Cheers;

Thomas Knox



________________________________
From: volt-nuts <volt-nuts-bounces at febo.com> on behalf of Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby at kirkbymicrowave.co.uk>
Sent: Sunday, June 26, 2016 3:29 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Keithley 2001 - do you need to open it to calibrate it?

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
xDevs.com | DMM noise measurement test project<https://xdevs.com/article/dmm_noise/>
xdevs.com
Test project of bench DMM noise levels evaluation, using DCV ranges and various NPLC settings.


> 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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