After many hours of troubleshooting my dead A4000 and scouring ebay for another one, I finally managed to find one I could afford. Unfortunately it was not quite as advertised.
“Used and working. There is some slight aging/yellowing on front of the case and light scuffs/scratches on top and sides of the metal case. This A4000 Will need a new battery, there is no corrosion on the battery or motherboard, sometimes it does take a few resets to bootup from the hard drive as ide settings are not kept, however the currently installed hard drive is a fast booting ide drive and will most times boot on first attempt/power on. The A4000 keyboard is missing r-alt key, and left amiga key does not be respond to ctrl l-amiga r-amiga softboots/resets, other than that A4000 keyboard responds fine to all other key presses.”
The battery had definitely leaked onto the motherboard. There was a lot of green corrosion on the legs of U891 and and the resistors and chips adjacent to the battery showed mild staining and scarring from the battery acid. The motherboard and case had a coating cigarette smoke and after hours of cleaning still smells like a pub. The computer also had a coating of birdseed inside. After two rounds with the air compressor and half a bottle of alcohol with four rags and a Q-tip, I was starting to have a little confidence.
Amazing, the old RAM sockets were still intact. So I put it all back together and put a DVD drive in it. I did have to replace the HD cable before it would all work. I ran Analyzer and the 18M RAM all tested good.
So finally I get to rejoin the ranks of the privileged Amiga 4000 owners!
Incidentally, I wanted to pull off the CPU card so I could test the old one. How do you get the darn thing off without breaking it in half?