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Fluke 731B Voltage Standard Restoration and Mods?

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TERRA Operative:
So, to add to all my other projects, I just picked up a Fluke 731B voltage standard..  :-DMM

This looks to be an easy one though as at a cursory glance, it just has the usual failed batteries (But they have barely leaked at all, so no real cleanup required) and on hooking it up to my 34461A multimeter, all the outputs are looking relatively within the ballpark of where they need to be (a tiiny bit out, but nothing that a session of holding my tongue at the right position can't fix).

So the reason for this thread is, I'm looking for advice on any mods that I should do to this thing while I have it on my bench.

I have access to Ni-Cd and Ni-Mh batteries at Akihabara, so there's no problems there. (Or maybe I should upgrade to 18650 lithium cells? Thoughts?)
But I have read that the voltage regulation in this unit is a little archaic by modern standards, what would be the possibility and benefit to upgrading the power supply for better regulation and less ripple etc?
Maybe even sticking a filtered IEC socket in place of the standard one seeing as I have a bunch sitting here on the shelf? (questionable benefit?)

Kleinstein:
As long as one can still get NiCd batteries, I would not convert to Li as this could be a mayor limit to transportation. So if at all it would be more like a removable option for in Lab use.
With NiMH batteries it may be a good idea to upgrade the charging part, as they are more sensitive to overcharging. Even NiCd cells could get better life with less stress. Modern cells tend to have higher capacity, but may not be as robust as the old ones.

Gyro:
SLAs? They are happiest being float charged.

beanflying:
KISS was the answer I came up with a NiCad powered HP 5000 series counter. I use a heap of LiPos in Planes and Helis but I went with NiMh (D cells). It was a size for size replacement and the NiMh cells handle being floated and from time to time I drop the power to keep them getting some actual use.

I went with the stock charge circuit initially but I am going to look at it again with a modern IC solution but as it is working well it is down the list.

HighVoltage:
I stood in front of the same challenge on all my 731B references and decided to stay with Ni-Cd packs, after I found some very nice packs.

https://www.eevblog.com/forum/repair/fluke-731b-dc-reference-standard-repair/msg1073583/#msg1073583

BTW, over the years I have owned 6 of these references and only two are without any significant drift.

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