My 301 got a thread jammed in the bobbin race as I was sewing. Cleaned it out, but now when I put the throat plate back on(the little thing-a-ma-bob is in the groove)she won't sew. Everything is free and works without the throat plate , but with the throat plate it's like it's frozen up. Any hints or ideas before I have to take her to the shop? I only have 3 blocks to finish and I would really like to get them done. Thanks Numa