I bought some (Dritz?) generic green plastic bobbins at Hancock that said they would work in my Viking. Seems like some of them do and some of them don't. When I have a problem my first correction is to put in a Viking bobbin. Usually does the trick. Worth the money to try. The Viking ones are ridiculously expensive! Come on, it's only little bits of plastic! I really dislike being stuck with an expensive name brand.