i don't have a Bernina, but it seems to me the upperthread is too tight, perhaps you can make the tension of the upperthread less.and i hope you use the special bobbin thread,so not a common thread on the bobbin.if this does not work.perhaps someone else can give you a better answer.

I agree with Gerry, your top tension may be too tight, but I don't have a Bernina. Jerrilyn does, I think, hope she comes along and sees this! Good luck, Marji

I have the same machine and I use various bobbin threads. I have used the prewound ones with the cardboard sides and the ones with no sides, also have wound my own. They all work fine in the machine. The only thing I have found is when the prewound sideless bobbin gets low on thread, then it tends to pull through to the top of the design. All I can suggest is that you play around with your tension, sounds as though it is too tight if it is consistently pulling to the top. If that doesn't sort it out then you would have to take your machine in to a dealer.

ttt for you, maybe somebody with a Bernina will see.

I had this problem with my janome,what you need to do is take your machine to Bernina,ask them to set your tension to the brand of bobbin fill you use,and stick to that brand. With some designs it looks better to use the same colour thread top and bottom.*

When this is happening with my Designer1 I have to losen the top thread tention. You have to fool around with it until you find the right tenon. There is a great tip page about this on the Embroidery Library site. It is under tips and projects. Title is Tenon Troubles. It helped me , hope it helps you.

Best advise as suggested by "toet", is to take it to your Bernina dealer.

Hope u solved your problem bkd. Tension problems can b a bummer *