Originally Posted by
newbee3
usually means the top thread is not threaded correctly or the tension need to be adjusted I would take out the bobbin and the upper thread and re thread the machine and insert the bobbin.
I would try this. If that does not work, it may need some adjusting by your Bernina dealer. I'd use the same color thread in the bobbin if it does not work after rethreading and adjusting the tension. That is what I do if I don't have time to take my machine in to be serviced.