OK, this is real weirdness, JDW.

I just reattached the power supply unit back up to the analog board and unplugged everything from the board except the power supply. I turned it on. Lo and behold, the fan is spinning.

So just picture in your mind the PSU and analog board laying on a workbench outside of the Mac, the video board (P2), hard drive power cable (P5), CRT yoke cable (P1) and logic board cable (P3) are totally disconnected from the analog board. I add AC power and turn the power switch to on. The cooling fan starts spinning and remains spinning until I shut the power off. Obviously, without the remainder items connected, it takes the fan about 3 seconds before it stops spinning, compared to instant off with everything hooked up and running. There's no sign of anything being fried or unusual noises, squeaks, zaps, etc.

I am telling you this now: I haven't done a single thing to the analog board or power supply, as far as soldering and replacement parts. All I've done up to now is check that there is output power from the PSU. I did earlier double check that the fuse inside the power supply was good (and it still is). Also, I did run continuity for the switch inside the PSU, along with the wires going from the AC jack to the switch. All that was found good, too.

I don't know if anyone has encountered this in the past. JDW, I don't have a copy of "The Dead Mac Scrolls", though I really should get one. I'm going to wait for a response before deciding to put it all back together and trying again.

73s de Phreakout. :?: :-/ : :rambo: |)