Replacing Coin Battery on Motherboard

I want to replace the coin battery on its motherboard, preferably, without losing time or BIOS settings (sorry, this isn’t a RISC OS computer). Any suggestions?

The crazy way: Swap it when the machine is running.

The safer way: Take photos of each setup screen (so you know what the options were) then swap the battery (machine off) quickly. Current draw is very little, so you might be in luck. If not, you have photos of how everything was.

If the problem is that you can’t get into the BIOS to change things, well…

or hold a reasonably sized electrolytic capacitor across the battery terminals while you swap it. That will maintain the battery voltage for long enough.

In my experience of dealing with these things, there’s a contact clip on the side, and a sort of raised pad (often just a slightly bent bit of metal) underneath.

If the two sides of the battery are accessible, a capacitor could be an option, certainly.

I vote for doing it the crazy way, but use ESD safe tools. Plastic tweezers!

Unless it’s a very old computer you can usually save the BIOS settings and load back after a reset. You’ll probably lose more time setting up for a “hot swap” of a battery than just a regular shut down, replace battery and restart.

The old battery registered 0.1V on a multimeter! I think the previous BIOS settings had been lost before I replaced the battery with a new one, and the BIOS settings were default ones.