I've never tried Deoxit on a keyboard, but last night I told myself that if the thing is just gonna sit around and not be used, I might as well try something. So I broke out my Deoxit, sprayed it, hit the key 3,000 times, and... it hasn't turned on the machine all night, so far. I'm going to keep it plugged in and hope it works now.
Also, something I discovered when I took off the top is that there is some kind of oil ALL OVER the inside of the keyboard. It's odorless and clear. The date on the back of this keyboard says 1989 but I'm unsure if that's when it was manufactured, but somewhere down the line someone spilled or sprayed something on the inside of this. It works fine though.
Going to keep my fingers crossed for now.