🚀 go-pugleaf

In <16644@ucbvax.BERKELEY.EDU> dlee@miro.Berkeley.EDU (David Lee) tells of
some problems he had with a Mac-plus.  He turned it on, got strange video
for 10-15 seconds, then the machine started to smoke.  When he brought it
in to be fixed, it worked fine, has has worked ever since.

	One possibility is some sort of momentary short in the high-voltage
section.  If you had some dust or something in the wrong place which
allowed the HV supply to arc, you might either produce enough EMI or drag
the power suply down enough to flake out the video.  If the dust burned
away all by itself, that would account for the machine working fine later.
This is just conjecture, however.

	Note that on high tension transmission lines, similar effects can
be seen.  Most high-power circuit breakers are designed to automatically
reset themselves after a short time, in the expectation that whatever
caused the short (fallen branch, out-of-control automobile, small animal,
etc) has either burned up or fallen out of the way.  A typical reclosing
program might include attempts after 1/15th (4 cycles), 1, and 15 seconds,
after which the breaker locks out, requiring manual intervention to reset.
-- 
Roy Smith, {allegra,cmcl2,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016

"you can't spell deoxyribonucleic without unix!"