changing battery on beige G3 desktop

See Mac PRAM, NVRAM, CUDA/PMU & Battery Tutorial

Your Users Manual should have the instructions. What exact model G3 do you have?

 Cheers, Tom 😉

I believe this link has the instructions to remove the cover.
http://www.macupgrades.co.uk/store/machine.php?name=powermac-g3-beige-desktop

 Cheers, Tom 😉

The battery is 1/2 the length of AA battery. You will find it in a holder under the back-end of the sound card. The retainer on the battery is "C"-shaped. It is removed by applying pressure along the long axis, away from the center.

This site is a little old, but has pictures of the battery and retaining cage. I think Tom's site has this link, too:

http://www.academ.com/info/macintosh/

I usually remove the sound card to have more room to work around the battery socket. It's kind of cramped in that area, you might barely have enough room to swap the battery with the sound card in place. The sound card is similar to a PCI card, but re-inserting it takes a good deal of force to get it totally reseated.

Pay attention to the orientation of the battery before you remove it, and install the new battery the same way.

Logic board diagram:

http://macgurus.com/products/motherboards/mbppcg3desk.php