Oldest operational computer was Re: cctalk Digest, Vol 54,

[Tony Duell]

> So the computer literally did not operate because of
> a burned out light bulb.  When I replaced the bulb,
> it worked just fine.

TO go completely off-topic, I have an old Heathkit PSU where the supply 
to the zener diode reference is itself stabilised by a gas discahrge 
tube (somethling like an OA2). And the series resistor for that tube is 
the (110V) power-on lamp. And yes, I was given it becuase it didn't work, 
and the reason it didn't work was that the lamp had failed.

-tony