I don't know your machine, but I have the Featherweight and it will freeze up with a very tiny piece of thread caught behind the bobbin case. And that wee little piece gets there when you turn the fly wheel backwards. (Which is something I do out of a bad habit trying to get the needle to raise up.) So then I have to take it apart, clean it out and start over. It can be very frustrating. But they tell you not to turn it the wrong direction. There may be a video to show you how to clean it out. There are a few vintage machine restorers on this website. Hopefully one will see your post.