Well, changing the bobbin tension didn't work, neither did jiggling the wheel. So I will be studying those videos very closely and will attempt to adjust the tension.
Too bad none of us live closer to each other! I do have a friend who is an engineer, and she is one of those people who will fix anything without hesitation. I may ask her to help me on this project, since she has a FW, plus she has dis-assembled many sewing machines and gotten them in good shape.