Nice find LCGuy - must have been pretty exciting to finally find a decent portable in your neck of the woods! A while back I found a 5x0 charger at a car boot sale for 50c, and posted it to iMac600. They are around - perhaps try Mactalk? I had about five 5x0s for a while, all donated apart from a 540PPC 100Mhz and my favourite 540PPC 167Mhz with Rev c card cage.

Anyhow, I have a 5x0 charger right on my desk! It says:

output Vmain 16V --- 1.5A

output vbatt 16V --- 1.0A

autoranging input 200 - 240V ~ 0.75A

JB