HP-71B battery drain with no extra RAM or ROM

[hpcalcuser83]

I do not have the HP-IL interface installed. I juat tried to put in new batteries into my calculator and I noticed that one of the battery terminals (not the ones with the springs) is missing. It was not like this before. I was able to power on this calculator a few months ago. I am not sure where the battery terminal went. It does not appear to be inside the calculator. Maybe this was the reason for the battery drain. Well, now I need to repair/replace the battery terminal. Anyone have any tips on how to do this? Thanks.

-Gil