I have looked into this after everyone in IRC assured me I didn't understand what you were trying to do.

The Quadra 8000 logic board uses a 2-plug PSU with cables, the same as the 840av (I checked the part numbers). The plugs are on the very top edge of the board as it is installed in the Q800, at the back by the speaker.

Following me so far?

Right. The Quadra 650 and IIvx both use a different Power Supply, that has one 8-pin connector that is mounted directly to the bottom of the PSU. This is a 'drop-in' type PSU that was also used on the IIc/ci/cx and also the 7100. The PSU connector is a good inch inboard looking at the 650's schematics.

This means that the PSU from the IIvx won't line up, won't supply enough lines to the board, and well... won't work.

I'm sure the board layouts for the Q800 and Q650 look similar but they are not the same. I have the Apple Service Manuals for all the 68k desktops and have double checked part numbers of PSUs against each computer.

Either I'm missing something vital here, or you are. One of those two is the case ('scuse the pun [] ]'&gt...