In article , Arny Krueger
wrote:
"Jim Lesurf" wrote in message

[snip system details]

Today, the fire control system fits on the back of a Humvee which also
powers it. It has about 5 times the range. None of the equipment is
routinely maintained in the same sense. Components basically run until
they break (rare) or are fired, and then they are replaced.

Really and truely the only difference is solid state technology and
other technological changes that it enabled.

In a parallel vein, when I started developing/using 100-400 GHz receivers
20-30 years ago for astronomy we used to use Klystrons that typically
lasted about 100 Hours each and cost a few thousand pounds each, and BWOs
that cost loads more and lasted a bit longer. More recently we just built
our own Gunn oscillators, which just run until we shove them in the
cupboard until next needed. :-)

(OK, one died when an MSc student insisted on applying double the required
voltage for long enough to kill the protection circuit, and then the
diode.)

The PSU's for the Gunns are loads cheaper and easier as well. Indeed, my
favourite Gunn PSU is the same design as I used to like for use in audio
preamps. :-)

FWIW My experience with domestic audio is that the main reliability
problems [1] are down to things like switches, contacts, etc. e.g.
essentially 'mechanical' in nature. With electrolytic caps wearing out as a
secondary issue.

[1] Ignoring 'hostile action' by the user. 8-

Slainte,

Jim

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