I could use some advice on how best to go about cleaning and repairing Alps switches.
Today I was testing a keycap on my recently refurbished Northgate Omnikey 101 with SKCM white Alps. I had put a "D" cap from an IBM 5140 on the D key, and then replaced it with the stock D cap. After doing this, the D key failed to register. All other keys registered just fine.
I pulled the cap and replaced it again to be sure it was seated properly. It still failed to register.
I then opened the switch, blew it out with canned air, put it back together, and still no joy.
Opened the switch again, cleaned the switch plate as best I could with 70% isopropyl alcohol, checked to be sure that the click leaf was not damaged in some way, reassembled, still no luck.
Opened the switch again and found that if I gently pushed the leaf on the switch plate toward the rear of the switch with a plastic spudger, the key would register. So I supposed that the problem was within the switch and not due to a broken PCB trace or bad solder joint. I tried gently pulling the leaf on the switch plate toward the front of the switch in an attempt to adjust the springiness, but the reassembled switch would still not register.
Finally, I replaced the slider, spring, and click leaf with the corresponding parts from a Matias Click switch and reassembled. Now the key registers. I am glad that this worked, but I do not know why it worked. Thoughts and suggestions welcome!