I was up late goofing around with a new sewing machine trying to get used to it.
My eyes aren't that good. I was having some difficulty putting the bobbin in place. Suddenly the whole area(hook assembly?)where the bobbin goes collapsed under my fingers and the bobbin was stuck in there at a crazy angle.
I almost cried. I thought I broke it.
Next morning I opened the retaining clips, let everything fall and reassembled and it was fixed!
I think what happened is when I was fumbling around trying to put the bobbin in I knocked a retaining clip loose.
I was just too tired to see what the problem was until the next morning.