Getting good bobbins is getting to be a problem. I use a sidewinder to wind bobbins - it works and is quick...
I had a bobbin problem a couple days ago. It was a new bobbin. The machine would sew just fine then all of a sudden it would jam. I probed and cleaned and probed and basically went over the whole bobbin area over and over - then I looked at the bobbin. There is a seam where the post comes together - it was rough and the thread was snagging on it.