I'm new to Hotrodders and I have a question regarding my Singer 111W155. I ran it backwards by hand and didn't realize that it would jam the machine. There is thread under the bobbin case and I can't figure out how to get out the case in order to remove the thread. I removed the throat plate and the "C" shaped piece that is held in by two small screws but it still doesn't pop up and come out. Is there an additional screw(s) that need to be removed?