In article ,
Don Stauffer wrote:
DoN. Nichols wrote:
.

Yep -- wire wrap was cheaper than custom PC boards in the
onesy-twosey world -- but was a lot of fun to debug. I've done enough
of that on my own hand-built boards.
.
I was also told that good wire wraps were more reliable than soldered
joints. By good, I mean by a certified wire wrap technician using
certified tools and materials. We used to use a lot of wire wrap on
space stuff for its reliability. Though I didn't work for the companies
that made the Apollo vehicles and lander, I have been told the main
Apollo computer was wire wrapped.

The phone company used to use wire wrap as "permanent"
connection, and soldered as "temporary". They used heavier gauge wire
and larger square pins, but the principle was the same.

The major problem with a wire-wrapped computer is that it is
*very* heavy compared to a printed circuit board. There are the square
bonze pins 1" long with a pin socket at the end, all the wire (longer
than a PC trace, and more metal in them), and the PC boards still
(usually) carried power planes. And -- the boards had to be spaced
something like 1-1/2" center to center, instead of the 3/4" which was
usually possible for logic circuits on PC boards.

FWIW, the early Bridgeport BOSS-3 CNC controllers were
wire-wrapped -- because they had not yet settled on a final
configuration. The later ones were PC boards.

In the boards which I made, I usually used yellow for all logic
level signals, black for ground and red for +5V. On one project for
work, yellow was for the address lines and blue for data lines (or was
it vice versa), and white for analog signals. I wanted all those
colors because others were wrapping some of the boards, and if they did
not work *I* was going to have to troubleshoot them. :-)

Enjoy,
DoN.

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