dead MB or dead CPU

A computer (pentium III, 733Mhz) is dead. I tried another Power supply and I removed all the interface cards (including video)and disconnected the floppy and ide connectors– I get no keyboard led activity and no error beep( not even the ‘plug a video card’ one).
AND I have no spare CPU or MB to swap and see what is wrong and the reset button does not seem to respond. Is there a way to ‘scope’ the MB to see which one is bad (I have access to a 30Mhz scope- barely better that a DMM)
This MB will not allow overclocking (slight ajustmtents available thru BIOS though)