Replacement Batteries for Datron 4910 DC Ref Standard

[Hawaii596]

I have a little of almost all of the above. My main 732A has history back to the 1990's. Matter of fact, when I get the Fluke "Hot Cal" done, when they provide me with the various uncertainties (down to 0.34uV/V now), they include its history back to the old original 1990s cals they did. It was "Cold Iron" (shut down and in storage) for a number of years while (around 2006 - 2012, I believe). I could see a little shift (stopped aging "some" (not all)) during that period. And there was quite a bit of time needed for it to get back to full stability again. It has a really nice linear prediction plot. I have a second 732A that I brought back on line a year and a half ago or so. As I have plotted it against my master reference, I found it has taken it really a year or so (maybe more) to find it's groove - in terms of a linear drift slope).

The problem I had with the 4910 set is that in comparison with my better 732As/Bs, it had a significantly larger drift rate even after a couple of years cook time. The drift on my master reference, by the way, is about 0.12 uV/V/Yr.

[CalMachine]

Wow that is a pretty remarkable reference you have there!  Pretty damn stable if you ask me.  You must be somewhat close to Fluke if you're able to hot ship the 732A.  I'm still relatively new to the game so I'm just now starting to build my history.

Thanks for the heads up on the differing long-term drift characteristics, as well as the most likely lengthy process of my 732A finding its groove again.  The oven is functioning and stable, atleast.

The 491x series still holds a special place in my heart, however

[Hawaii596]

I don't ship my 732A ("Master Reference"). They overnight their traveling 732B along with their set of comparison cables. I do the "Hot Cal" on my 732A in place. It is pretty stable. I am hopeful that the other active 732A finds its groove. I have a couple more 732A's not in use, and the 4910 mothballed as well.