X-ray: Thanks for your support
odin: Ok, I will get the battery out first thing tomorrow (it's getting late here and I have packed away the A4000 in the corner of my working table). Thanks for the help and the link to the A4k site - it's quite interesting.
Also, I will mention that I have made some (slight) progress earlier tonight with the A4k:
1. I got the A4k going (fan runs and power light comes on), and the hard drive comes on (I can hear it spin) by fiddling with some small connectors which I can join together (but there are some of these connectors which I don't know what to do with - there are several of them altogether).
Anyway, the computer turns on, but nothing else happens - I have my old Commodore monitor (which I know works as I use it with my A2k) connected to the A4k, but nothing comes on the monitor.
2. I found another hard drive in the storage room, which my father told me was a spare which the Amiga techician used when he was trying to repair the computer many years ago (obviously a failed attempt which I am hoping to better). This drive works (spins up), as does the internal one which is mounted in the A4k.
3. I also found a CD drive which fits in the bay above the disk drive, but I can't make it (the CD drive) do anything except for the green "on" light come on - it won't eject the tray or anything. Some other things I found also an "OpalVision" card which I have no idea what does - any ideas? and also an Emplant card of some sort (I'll try and get specific names of all these things in the morning)
^ I know some of the above points are probably hard to understand, so I'll take some pics in the morning of the setup, and I'll post 'em here in this thread so you get a better idea of the situation