Be sure to use the correct colored wires for the valtages you'll need to power the A4000 with, I believe it's a +5VDC, a +12VDC, a -5VDC and ground. Could be wrong on the -5VDC however as I think the A4000 has a Power_ON good line which I think you can use the AT Power Supplys Sense Line with.
I think there are still some adapters out there that will convert the AT power output to the proper pins/connector on the Amiga side. Can't remember where I saw the link at however
