It’s doing it again tonight and I have noticed that the bobbin when set and coming up thru the feed dog hole, is very loose. Like no real tension at all. The top thread has tension. My question is, how do you tighten the bobbin tension? The only thing I remove from the bobbin assembly is the bobbin itself, so I can’t do the drop test. It just falls straight to the floor. Something is off. And there’s a great chance that it’s me!