Well, I'm running a custom jobbie ;-)
No fan, HUGE heat sink. 25MHz CPU overclocked to 8^H40MHz. CPU is soldered on, so cannot clean that socket. Tried booting without RAM, which doesn't help. (CPU never comes out of reset, it seems)
I'm a research and development engineer in electronics, so you would THINK I tried the usual tricks :-)
I guess I'll have to take it with me to work (along with the A1 for more linux-hacking (already have a private RS6k in the office...)) and check it with an oscilloscope...
I suspect the CPU might have been damaged by the stupid clock chip being loose (I don't know how well the 68040 handles 0MHz clock over a long period of time...).