Help! I am quite frustrated with my Artista 640. I had problems with it last year in that the "lint in the bobbin area" warning kept going off even though I cleaned it and oiled it. I was in the middle of a very important quilt so I took it in to my Bernina dealer for service. While they were looking at it, out of frustration (because I was on a short deadline) I bought a Bernina 440. I took it home and it saved the day while waiting for my 640 to be fixed. When it was fixed it came home and rested in it's case while I continued using the 440. Last week I took the 640 to a 2-day class and it performed like a champ. When I got home I started using it again as my main sewing maching, or at least I tried to. The same warning about "lint in the bobbin area" keeps going off and I can't sew! I've cleaned, oiled, and inspected all the areas I can. Is there anything else I can do other than driving the hour long trip back to the Bernina dealer? I'm so frustrated!!