DS2250T with a DS5000 8051 variant.

[syzygy]

I remember reading something that you need to activate the DS5000 (or maybe it was the RTC on the DS2244T)

uh-oh . I assume, or hope, that means resetting the encryption, that can be done using the monitor [Grounding *PSEN and reseting].

 

[syzygy]

So, I managed to replace the battery; again, just to see if I could - not because it wasn't holding time and RAM, but it does have a 1991 date code..

BLUF: Given the board holder, there is very little room for extra thickness. I probably could have tried some double-sided nano tape or dots as @gertk, but I went with what I linked in post 19. It is hard to see in the pic but after a 24h cure time, I think it should hold up well.



There is so little board thickness to spare, I had to remove the ring cover off of the battery. Note that the original battery did not have that ring.



The good news is that it worked like a charm. As expected the time was garbage, but once set, all is well. So, now I know how to change the batteries on these boards if I need to do so.