Odd thing is that everything seems to work - if I
place a small fan
to keep the CPU & FPU cooled to "just hot", it settles back down and
all seems to work correctly. All self-tests pass (including FPU).
It appears it would run indefinately in this state, but it's
obviously not healthy. It seems unlikely that there would be an
internal chip failure that would cause it to eat this much power and
still perform it's intended function.
Yes, that's why I speculated about fans - perhaps it's designed for
(say) three times the airflow the case is giving it, and the only real
problem is the fan? It strikes me as unlikely, but no more so than any
other failure mode I've come up with that matches the symptoms.
Do you know that the fan is the original one? Is it possible that
somebody has replaced the fan with a lower airflow one in a misguided
attempt to make the machine quieter?
-tony