Janome folks:  A big THANK YOU for those who read my thread regarding the bouncing, noisy bobbin. I am sooooo glad the problem has been solved by the shop.   I appreciate all the suggestions and comments.   I will tell you that I have stopped using generic pre-wound bobbins, even Janome pre-wounds. After checking the pre-wounds in my stash, I was somewhat amazed at how poor the quality was--most had some sort of flaw or burr present.I then purchased a box of the pink, Cherry Blossom special edition bobbins and a spool of Janome bobbin thread and wound my own bobbins.  I use the pink bobbins exclusively for embroidery, so if I see a pink bobbin, I know it is Janome 90 weight bobbin thread on it. The pink bobbins come in a good plastic, see-through box, so I can see at a glance what I am looking for in my sewing drawer.   I should say that I have quit using the pre-wounds for embroidery, but I have not encountered any problems with generic or other pre-wound bobbins for my sewing-only machines----a Janome Skyline 7 and a Pfaff from the 80s.  Neither of them do embroidery; they are reserved for ordinary sewing.    Nevertheless, I also ordered a bag of  25 Janome branded bobbins which I will phase in as the generics and pre-wounds are used up.  In for a penny, in for a pound, as they say. Might as well use the Janome brand with my Janome machines.
Happy stitchuing!!
Kathy Strabel   Camas WA