I have a singer brilliance 6180. It hasn't been used in years, but we recently got it out to give it a chance. When my kid fired it up, they got a c4 message? So I opened up the bobbin area to make sure there was no jam, and put it back together. That's when we realized the handwheel is stuck! For some reason I am having extreme difficulty finding anything other than "make sure there is no bobbin jam" in the advice category. If anyone has any ideas, we would truly appreciate it! Thanks so much