[volt-nuts] RE "new" 3458A

[Richard Moore]

Hi Randy -- sounds like your unit is in cal, based on your measurements 
of DCV and precision 10k resistor.

Using autocal all is recommended before doing precision measurements, 
and I do that if it's been more than a day or two since last use. The 
autocal uses the internal Vref and an internal 10K resistor to do cal on 
everything else, so that tells you what the basic cal procedure is. I 
just got my 3458 back from Loveland, and that's what they did for me -- 
warmed it up, then ran autocal, then measured everything against a Fluke 
5700, aided by an HP 3325, and another 3458.

It has been 5 years since I replaced the display board (no "exchange" 
deal was available then AFAIK, so I don't know what's changed) and also 
the NVRAM board, which was dead, with one with the Snap-cap RAM chips. I 
did those replacements, then sent it home for cal, which was complete, 
since all the RAM was new. Now after 5 years, the unit passed all 
incoming performance tests and was sent back to me without a cal process 
of any kind. This tells me that an old, well-aged Vref module is a good 
thing. The 10VDC test had changed by a bit under 5ppm, or roughly 
1ppm/year.

They have a cal deal -- use code 1.090 -- press them for it -- and that 
saved me 30% off the normal price. I think this deal lasts until 
mid-September, so my recent "cal" ended up at just under $400 including 
shipping. I'm not sure the deal is available on new or first-time cals; 
my unit was in their data bank.

But this is a long way of saying I don't think you need to send it for 
cal -- just push Auto Cal and Enter and wait about 10 minutes and you 
should be good to go.