[R-390] Stuck linearity coil piston: SOLVED!

[Tim Shoppa]

OK, I got home, gave the kids their snacks so I could have 5 minutes
in the basement, stuck a nail into the top of the linearity coil and
gave it a couple of whacks. Piston frees up and comes out the far
end. It was coated by a layer of grease/shellac, some acetone and
brake cleaner helped clean it up and now it works great.

I do not NORMALLY use a hammer to solve my R-390A problems :-).

Tim.