There are silver plated metal contacts with indeed a little stud, and a carbon pad on a silicone dome.
https://youtu.be/n_oyDYRDYzs bkw On Sun, Jul 6, 2025, 6:27 PM Andrew Ayers <keepe...@cox.net> wrote: > I've never taken a 102's keyboard apart, nor have I seen the "insides" > like you describe them, but that little thing in the rubber cap you > mention as a "metal stud"...likely isn't metal. > > Based on keypads and other similar kinds of "button devices" I've taken > apart (remote controls, calculators, etc) - it's actually some kind of > plastic or rubber compound impregnated with carbon. It does actually > complete the circuit, as you stated. > > But I've also found when I've tried to bridge such a circuit with just a > piece of metal...getting it to work can be "finicky" - assuming in your > case it works at all, and the break isn't somewhere else. > > Cleaning of the contacts as suggested is a good step, though I don't > know if you need to necessarily use an eraser; they tend to be abrasive, > which in the case of cleaning contacts you'd think would be okay, but > realize that the metal layer of those contacts is very thin. One such > "cleaning" won't harm it, but do it enough times...hopefully that won't > be needed or necessary, of course. > > You might try just using the alcohol (and a swab), first (I have a > "thing" when cleaning things, especially if solvents and plastics are to > be involved: start with the least harmful first, then move up the chain > - that's usually either soap and water, or rubbing alcohol; end of the > chain, of course, is a right angle grinder and/or "blue wrench" and/or > BFH). > > Regardless, try also some rubbing alcohol on that little stud, as it can > sometimes get dirt and/or other deposits that can prevent the circuit > from being made. > > Good luck! > > Andrew L. Ayers > Glendale, Arizona > phoenixgarage.org > github.com/andrew-ayers >
