ok....an interesting twist. I pulled out the AFM to move the measuring plate around...and its CORRODED shut!! barring pulling off the bottom plate held on by a crap load of small screws, what is a safe way to clean out the corrosion and get the plate open..?

FWIW, I got it to move maybe a 1/16" by force and thats as far as I could move it without fear of breaking stuff.