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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