When we first got my F.W.221, I thought I could take the bobbin out and clean and do all sorts of things; just like my old Stradivarius of 1961. Not true; I had to take it to the repairman who got it going again.
Don't know what he did to it, but he carefully instructed me to" just take the bobbin out; don't take the whole thing apart. When you need to clean and clear out the dust, lint, ect, get the canned air from Wal-Mart or Big Lots, and that will do it."
I honestly don't know what you need to do now, but bet some of the other gals will knowQ!
Good luck!
Mariah