[volt-nuts] HP 3457A calibration?

[J. L. Trantham]

Joe,

You might start with just measuring the battery voltage.

There are two different batteries used in the 3457A, one that is obsolete
and the other still obtainable.  Per the manual, there are two resistors
that need to be changed if switching from the 'obsolete' battery to the 'new
battery'.  However, I wonder if the resistors even need to be changed.

See message #48954 in the archives and the several messages surrounding
that.

If the battery is 'OK', I would favor just sending it to Agilent for
calibration, unless you can 'SAFELY' change the battery while preserving the
cal data.

Good luck.

Joe

-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of Joseph Gray
Sent: Monday, August 19, 2013 10:16 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] HP 3457A calibration?

Someone pointed out in the comments that his DMM was probably calibrated
once or twice at the most.

>From looking at what is on this guys shelf, he has way more money than I do
to spend on test equipment. I'm jealous :-)

Speaking of too much test equipment, that guy Dave who does the EEVBlog
videos also has a lab to drool over. I don't know what he does for a living,
but he seems to be more knowledgeable than the guy from South Africa (who is
also long winded and boring).

As for the "cheaper" solution, I just bought a 3457A. I expect to see it
this week. After checking it out for a bit, I'll be sending it to Agilent.
Although it may seem ridiculous to spend $200 getting it calibrated, I
figure that I'd be better off having Agilent do it this time, so I know
where I stand.

I'll have to read the cal counter before and after sending it to Agilent.
I'll let you know the results.

If the battery looks original, I'll have to change that out before sending
it for calibration. I know that I have to keep the SRAM powered, so I don't
loose the data already there.

Joe Gray
W5JG



On Mon, Aug 19, 2013 at 7:59 PM, J. L. Trantham <jltran at att.net> wrote:

> Interesting video.
>
> His 'cal certificate' shows no data other than 'in tolerance' and the 
> 'standards' used to established that.
>
> He also makes a point of the 'calibration counter'.
>
> On the 3458A that I was able to 'kill' the 'cal RAM', the 'cal 
> counter' was at '1' when I received it.  When I finished doing my 
> 'home cal' on a 'blank'
> 'cal RAM', the 'cal counter' was about 20 or so.  It appears that 
> every measurement that is calibrated increments the 'cal counter'.
>
> I don't recall how many ranges the 3457A has but add them all up and 
> that is what I would expect the 'cal counter' to increment by once you 
> finish a 'home cal'.
>
> Since Agilent does all this via HPIB (at least that's what I think), 
> it increments the 'cal counter' only by '1' step.
>
> I would opt for a 'cheaper' 'seems to be working' 3457A then send it 
> to Agilent for their calibration rather than spend extra for someone 
> else's calibration.
>
> Joe
> WB4BPP
>
> -----Original Message-----
> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] 
> On Behalf Of Joseph Gray
> Sent: Monday, August 19, 2013 8:20 PM
> To: Discussion of precise voltage measurement
> Subject: [volt-nuts] HP 3457A calibration?
>
> Recently, we were discussing where to get a DMM calibrated. Someone 
> mentioned an ebay seller in Albuquerque who had their meters 
> calibrated across town by a company with a similar name.
>
> I am currently watching a YouTube video about the HP 3457A. At around 
> 7 minutes, take a look at the calibration certificate when he holds it up.
>
> http://www.youtube.com/watch?v=HfxpJCdgVwc
>
> Joe Gray
> W5JG
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