You might want to check your manual as to how the bobbin goes in. I have a Janome 6600 MC and the bobbin will only work if it is in with the thread going to the left. Hope I explained this right. Also, as I am sewing yesterday all of a sudden my machine decides to act up and gives all sorts of trouble with nesting thread in the bottom and many things went wrong-long story short-I re-threaded, changed needles and put a new bobbin and all is well and working smoothly again. Also, my tension was off. Good luck to you