I just got a Singer 221-1 Featherweight, took it out of the box and sewed a little and it worked fine. After sewing a while I got thread tangled around the bobbin, took the throat plate loose to get the thread out and the bobbin out. The problem is when I tried to put it back I guess I'm doing something wrong so I read manual and tried to follow instructions to replace the throat plate with the finger position of the bobbin placed in the correct positon of the plate but when I do that nothing wants to turn. When the plate is out everything turns. Please help.