18 Aug
2006
18 Aug
'06
9:09 a.m.
Dave McGuire wrote:
Yeah. Before starting work each day, you would remove
your wristwatch, wedding ring, belt buckle, etc. Sure,
everything was "low voltage" (I think the pin drivers
max'ed out at 64V -- or maybe 32? The power supplies
were digitally programmable so it was some nice binary
number...). So, you weren't worried about getting
electrocuted but, rather, *cooked*!
One of my buddy's could never get his wedding band off
so he would have to wrap it in a bandaid. Of course,
bandaids are (back then) pseudo-flesh-colored so the
standing joke was that he was having an affair and
needed to keep his wedding band/marital status out
of view! ;-)
And it's all (deliberately) point to point so it's truly
tangled.
I still am unconvinced that the beast could actually *work*
given that *apparently* random fabrication technique (the array
was clocked at 100MHz -- no, it must have been 125MHz because
the cycle time was 8ns). Perhaps the designers had carefully
considered *placement* of the components and thus indirectly
influenced signal lengths, etc. <shrug>
TIP: An embroidery hook works wonders for fishing wirewrap wires
out of a nest without too much damage! ;-) (but you have to
find the right size hook to ensure a "good grab" on the wire)
<grin>
I worked on a "600 pin tester" (i.e. be able to
stimulate and monitor the states of 600 different signals
on the unit-under-test) in the late 70's. The "stimulus
memory" was two "doors" (large -- ~18" x ~60" -- wirewrapped
panels on hinges fed with *thick* copper bars for power
distribution) full of bipolar & ECL memory devices.
I.e. *hundreds* of amperes.
Holy cow!! When the
boards came in from the wirewrap house, there was a
short between two of the supplies (or, perhaps, a supply
and ground). Trying to figure out *where* the short could be
in a panel of that size COVERED with teflon wires was HUGELY
intimidating!
This I can also imagine! I remember how much trouble it was to find
wiring errors in Unibus-sized boards. If I recall correctly we had an
average of 350 chips per board, and tens of thousands of wires.