Sorry for yet another Sol-20 keyboard thread, although I feel like my problem is unique and might provide some help for others. When I first got my SOL-20, the TexElec keypads were out of stock so I decided to punch out my own foam-and-foils. I tried my best to follow guides but when I installed them, but most of the keys did not work and some of the keys would press multiple keys at a time.
I then decided to remove them and I bought a French-Canadian New Old Stock Sun Type 4 keyboard and I harvested the pads. I installed all of those and not a single key is working. Interestingly enough, all of the keys work properly when the bare PCB is touched by my finger. If I use some of the loose foil-foam pads I can only activate the keypress if I completely compress the foam pad on the key. Is that normal, or should it be when it first touches? I have a few possible ideas/theories:
I then decided to remove them and I bought a French-Canadian New Old Stock Sun Type 4 keyboard and I harvested the pads. I installed all of those and not a single key is working. Interestingly enough, all of the keys work properly when the bare PCB is touched by my finger. If I use some of the loose foil-foam pads I can only activate the keypress if I completely compress the foam pad on the key. Is that normal, or should it be when it first touches? I have a few possible ideas/theories:
- The PCB should be sanded down, with fine grit sandpaper. (I have tried this on a few keys but do to the nature of capacitive switches I am unsure if this would help)
- The PCB should be cleaned
- One of the 18 screws is somehow shorting a connection on the PCB
- A capacitor responsible for the "capacitive tolerance" of a valid keypress is damaged and should be replaced