Since I suspect that the keyboards were originally done by silkscreening
conductive ink onto mylar, it should be fairly easy, albeit time
consuming, to make a new mylar. My guess would be to use something like
a Houston Instrument Pen Plotter that would also take a vinyl cutting
knife, cut out the mylar, make up a screen, and just silkscreen the
traces onto the ready to insert mylar. Or, if the old mylar is not
broken, just reuse the old one. I don't know what kind of prep needs to
be done in order for the ink to adhere to the mylar, but this (and
anything else that comes up) is something that has been done for a long
time.
Another thought would be to go to someone who already produces this type
of switch and find out what it would cost to make up a couple. It might
be possible (depending on the size of the company) to get it done
gratis, ie as a sample.
On 7/11/05, Dwight K. Elvey <dwight.elvey at
amd.com> wrote:
If that didn't work, a last resort might
be to use some small wire wrap wire and melt a channel
into the plastic layer to keep from deforming the stack
too much
I've seen the results of attempts at that. Let me put it this way -
try it right before you are ready to pitch the whole mess.
there's not enough pressure to make contact between oxidized traces
printed on mylar and any kind of wire. The mylar sheeting is thin
enough that you are more likely to perforate the mylar than "melt a
channel" _Perhaps_ some kind of foil overlay might work, but it would
have to be akin to gold leaf, and you'd need a solder alloy that
melted below the temp of the plastic to get any sort of joint. For
that matter, if you had an uber-low-temp solder (200F? 300F?), you
might be able to overlay entire traces with WW wire, but not if the
plastic develops holes.
-ethan