So, I finally disassembled the A3000, removed the motherboard, and soldered on the coin battery holder. It was a major pain to disassemble the thing:
1. Everything was going pretty well into I got to the two screws on the motherboard (the hexagonal standoffs came off without a hitch). I couldn't get them out and they were badly stripped. I took my Dremel and cut flathead notches into the screws and was then able to remove them.
2. Cleaning the solder holes turned out to be harder than I thought. The two holes on the + side cleaned easily, but the ground hole was pretty damaged and while I could clean it from the bottom, couldn't make much headway on the top. So I took a wire nail, put it into the bottom hole, and gently hammered it into it until it poked through the top of the board. I then cleaned the rest from there.
3. My hand slipped a few times and went across a few traces but fortunately, no shorts and the solder mask was pretty much still intact.
4. The moment of truth came and I powered it on and -- nothing. The power LED flashed rapidly and I thought I saw a yellow screen briefly. I thought I was screwed but then I realized I forgot to put the expansion riser card in. Once I did that and connected the hard drive (another thing I forgot to do), everything was fine.
Those guys saying that the A3000 is a pain to work on are 100% correct. Very cramped and uncomfortable, especially the short SCSI ribbon cable.
While I had her open, I did take notes on the various chip revisions I have. Here they are:
Buster: 07
Gary: 02
DMAC: 02
Ramsey: 04
Which ones should I replace? I know there is a version 11 of the Buster, but if I find that, will I have to replace some of these other chips for everything to work OK?