Janomes have an oil wick hole under the bobbin case. The wick dries out, causing the bobbin case to jump and rattle and then jam. Nowhere in the manual does it say to oil this spot but if you do, your machine will settle down and sew without further problems. I ruined a bobbin case (needle went right through during one of the jumping and jamming sessions) before I found out about this spot. Even my dealer didn't tell me to oil it there. All they told me was that it was operator error, which it wasn't!