reading the schematics and technical manual, it seems like the metal assembly that houses the power plug also houses the AC input filter? if so, i'm getting continuity between the ground prong of the power plug and the exterior of the assembly. would this be a simple repair or should i consider replacing the power supply with the ATX conversion i've been reading about?
The input filter is indeed also the receptacle. The ground should be connected to the chassis of the filter, if it isn't, you have problems.
Let's do some gross diagnostics, obviously you have had the power supply out of the terminal, right? Did you try setting it on a non-conductive surface, plugging it in, disconnect the Molex connector hooking the receptacle, fuse holder, power switch, etc. from the power supply. Now power it on. Check for blown fuse. if the fuse blows you know it's in that little group. Fuse didn't blow? Reconnect to Molex and turn it on, fuse blew? If so it's the power supply board.