Oddly enough, the E2-key on my EII didn’t trigger as it should, it was triggering very randomly. I suspected this was due to oxidation and opened up the EII.
Removal of a key is simple, but you have to be careful not to break the now 30 year old fragile plastic. You simply push the key downwards at the front, and then pull it backwards towards you.
I removed both the E2 key and its neighboring F2 key to get a better view. Underneath the key there’s a rubber mat which the key pushes on. Underneath the rubber mat is a small metallic surface that pushes another surface on the EII which results in a contact.
Lifting the rubber mat showed serious oxidation on the surface on the EII. I sprayed a cotton swab with electronics cleaner and cleaned the surface from oxidation. After that I put the keys back to test if the problem was solved, which it was!
When the keys were loose, I cleaned them from 30 years of dirt. I was tempted to remove all keys and clean them, but I thought it’s an unnecessary risk due to the keys being fragile.