I have 3 different Janome machines, a Memory Craft, the 6600 and the AQS. On the 6600 and the AQS, I am frequently having trouble with the bobbins when they get towards the end. The bobbins are Janome brand bought at the Janome dealer and are wound on the Janome machines. They look perfectly fine but when it gets down to maybe 10%, it starts making a mess all over the material and knotting up. Once I put in a new bobbin, everything seems fine. I've cleaned out both machines. I just don't understand why I'm having the same problem on 2 different machines. Any ideas?