Having looked at my 122-key Model F, I found that two of its keys had problems; the Caps Lock key, when pressed, did not click, but only made a sick sproing noise, and the Enter key in the numeric keypad did click - but tended to stick in the down position.
All I had to do with the Caps Lock key was remove it and replace it, then it worked normally.
With the Enter key, the problem was the levelling device, so removing it and replacing it carefully, and getting the levelling device right (I had to do it twice to get the spring right; the first time, it didn't do anything) eliminated the sticking problem.
Now I will see if this keyboard can be connected to a PC without too much in the way of conversion electronics; I am hopeful, from some of the information seen here.
There is, of course, no fundamental technical reason why Unicomp couldn't make 104-key keyboards using Model F technology, but that would be very unlikely. For one thing, the Model F is significantly noisier than the Model M: I had forgotten that little detail about how you could actually hear the springs springing back on the older keyboards.
