I put my new 1391401 (9/7/90) back together. All the keys work from an electrical standpoint, but I'm having trouble with the two shifts and Enter. If you strike them at their outside edges, they often seize-- failing to go down unless you provide an astronomical amount of force, or sticking entirely.
The two shifts are a lot worse than "enter", and there's a little bit of the problem on the top haves of "+" and "enter" on the numeric area.
My "reference" 1391401 doesn't have this fault.
Will it wear down over time? It seems to be opening up a bit as I smash it while typing this post.
