replacing 71b batteries without losing data

[rprosperi]

You definitely must connect the AC adapter when swapping batteries, else you will lose MAIN RAM. Sometimes, if you're quick, it is possible to swap batteries w/o adapter connected and not lose contents of IRAM modules, but I have never been able to swap batteries w/o losing MAIN RAM, even when new.

I have heard/read that simply swapping one battery at at a time, rather than removing all 4 at once, and installing new ones as you proceed to do all 4 can will work, but I have not been able to pull this off. But I don't try since I have an 82059B plugged-in and always ready on the desk.