I have seen old Pentiums run at the wrong core voltage, and they would
work, maybe hotter or less stable. It could be a shorted regulator
putting out 3.3V to the 1,5V line, not sure if a P III would hold that
but it might work for some time.

David wrote:
Actually the most of the inductors described are not noise filters at all,
but part of a switching power supply regulator that converts either 5 or 3.3
volt supplies to lower voltages such as 1.5 volts for the CPU. They often
operate at high currents (perhaps as much as 10 - 20 amperes). There are
also some boards that have regulators to generate higher voltages for other
components on the board such as built in audio or RS232 ports. I have never
seen one get hot enough to cause smoke without also something else wrong. My
guess is that particular regulator was associated with something other than
the main CPU/memory system or else the machine would not run. Do all of the
I/O ports, built in peripherals, and add-on cards operate?

David