Front panel switches - what did they do?
Jon Elson
elson at pico-systems.com
Tue May 24 21:09:38 CDT 2016
On 05/24/2016 02:15 PM, Eric Smith wrote:
> On Tue, May 24, 2016 at 1:08 PM, Chuck Guzis <cclist at sydex.com> wrote:
>> Yes, but there was a trademarked name for the process that slips my
>> mind. Capable of very high densities.
>
> Multiwire?
>
No, multiwire is a process where lots of wires are laid down
on a PC board coated in uncured epoxy. When all the wires
are in place, the epoxy is cured in an oven. Then, the
board is CNC drilled, and the through-holes are plated. The
wires are what is normally called "magnet wire" with an
enamel coating, so they don't short to each other.
Drilling through the wires leaves the end bare copper, so
the plating process connects to all wires that pass across
where the hole is drilled. It is quite amazing that it
works at all! The one downside is that rework of the
boards, as in replacing chips, is a VERY delicate operation.
Jon
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