I've been having the same problem with my Janome, I took it in and had the bobin case replaced but it still dosen't work right, I thought it was something I was doing wrong but it seems like others have had the same thing happen. I have the 6500. :cry:
I bought a Bernina 440 and just love it, I don't have any problems at all with it. I loved the Janome till I started having problems I'm so glad to know I'm not the only one that has had that happen.