[cctalk] Re: Conductive material in rubber dome

Someone else responded directly with me and the same suggestion but provided a link on amazon. So, I'm going to go with both your suggestions. Thanks, Daniel sysop | Air & Wave BBS finger | calcmandan(a)bbs.erb.pw On Wed, 26 Nov 2025, Adrian Godwin via cctalk wrote: > I don't know what the internal construction of the TRS-80 keyboard is but > there a number of products targeting remote controls with a > conductive-rubber bubble over a gold-plated pcb. > > These vary between paints, entire keypads and small conductive rubber discs > which cover the original rubber patch. As long as the bubble hasn't cracked > but only the conductive material has worn thin, these last seem as though > they might be the best and least invasive repair option. Easily available > on ebay, some from reputable suppliers - maybe chemtronics ? > > https://www.eevblog.com/forum/repair/best-method-to-restore-conductive-keyp… > > On Wed, Nov 26, 2025 at 1:10 PM me--- via cctalk <cctalk(a)classiccmp.org> > wrote: > >> I just acquired a TRS-80 model 102, my first of that model. >> >> Everything is great other than three keys. The 2 keys works >> intermittently, >> q, and [ don't work. Having checked the schematic, the keys have no >> commonality on the circuit. >> >> Before I pull the cap off the switch, I know that the rubber dome inside >> has >> material on the inner part that meets with the silver contacts to complete >> the circuit. I'm told this material will wear out or lose conductivity. >> >> I reflowed the solder joints on the pcb and this didn't help. Other people >> have simply replaced the rubber dome from another dead 102's keyboard. >> But, >> I'd rather attempt applying new material inside that dome. >> >> I'm hoping there is an inexpensive and mainstream solution I can buy at >> home >> depot or something. >> >> Any tips? >> >> Daniel >> sysop | Air & Wave BBS >> finger | calcmandan(a)bbs.erb.pw >> >