I know some machines can't be taken apart by the uninformed - ask me how I know. Hubby and I took the top off, under where the thread goes and we didn't know how to put it back right and DUH - it wouldn't work. Had to have it fixed. I saw an offer for a book by a man that told how to repair machines, I sure wish I would have bought it. You might find a book in a library or google to see if there is any on line.