[volt-nuts] Old HP3458A - SN: 2823A 03939

[acbern at gmx.de]

well, I do that with my references if they cannot be adjusted reasonably such as the 732a. but for meters and calibrators I do not. 
achievieng high precison with such an instrument then means you still need to characterize it (i.e. calibrate, and not adjust it, doesnt save money essentially)
and secondly you always need to apply a transfer factor, i am too lazy for that, i rather get it adjusted when i cal it.
also, the reference is stable, true, but other things do drift, and we talk 10+ yeras here (last cal sticker i saw). it would certainly be interesting to know where its different ranges went inbetween (if it was known that it was adjusted to within spec back then, which probably is not known)


> Gesendet: Mittwoch, 08. Oktober 2014 um 10:32 Uhr
> Von: "Mike S" <mikes at flatsurface.com>
> An: volt-nuts at febo.com
> Betreff: Re: [volt-nuts] Old HP3458A - SN: 2823A 03939
>
> On 10/8/2014 4:23 AM, acbern at gmx.de wrote:
> > the EPROMs are in sockets, no soldering needed.
> > but again, buying a precision instrument but reprogramming cal data that is years old does not make any sense.
> > unless of course if you are just a collector and do not use its accuracy.
> 
> It makes perfect sense, for the same reason that HP doesn't touch the 
> cal if it's in spec - for tracking/characterization. By keeping the same 
> cal constants, if and when he does send it in for calibration he'll be 
> able to know how much it drifted since it was last cal'd (25 years ago?).
> 
> -- 
> Mike
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