23 Jan
2004
23 Jan
'04
6:11 p.m.
On Thu, 2004-01-22 at 19:01, William Donzelli wrote:
Will do!
THe electronic
design was abandoned for now. Basically I was to
(will...?) build a 4 x 4 switched cap memory which will be a nice
reality check on flops, tubes, etc.
Please keep us informed. Subminis might also be a good choice, if you can find
them. They "never"
go bad. I don't think I have ever found a bad one. Their reliabilty was
due to production in a clean room environment using very high purity
materials. One interesting side effect was that submini tubes lost their
sockets - the things were soldered right into the circuits, as the sockets
became the most failure prone components.
They are a good choice. The US gubbamint just (well a year or two ago)
dumped huge amounts of them, allegedly spares kept for existing equipme
nt went over 20 yrs old. There were some ship-board computers built with
them, soldered right into the PC board. Hell they're rugged, as they
were first developed for proximity fuzes in torpedos and shells!
Most computer tubes were also built in the same clean
room environment,
and also tended to be very reliable. In the good old tube computer days,
there would be a flurry of tube swapping for the first few months, maybe
a year, of the computer's life, but then as the weakling runt tubes were
purged, the machines became quite reliable.
I can totally see that scenario.
The biggest advancement was the use of the IERC tube
shields - the type
that have ribbing inside to conduct the heat away. It took ten years, but
the industry finally figured out the old style tube shields were a really
dumb idea.
Yeah, glass is a poor conductor of heat! I suppose lots of forced air
works too, but is always trouble.
The military radar things, specifically for IFF
systems, had good power
supplies. They were digital system, after all (specifially SIF encoders
and decoders).
See?! :-)