It's about a 1950 modle. One of the black metal machines. I put my bobbin in backward and the thread all jamed up. Now my machine is locked up. I can hear the motor running but the needle will not go up and down. I removed all the thread from the bobbin case area but can strill see a small piece of thread peeking out from the bobbin housing. I tried to remove this with tweezers but the tread is too stuck. Is there a way I can fix this myself or do I need to take it into a repair man. Thank you in advance for your help.