When all else fails, ask the ladies and gentlemen on the board. I'm having a problem with my machine, both the upper thread and bobbin threads are skipping, sometimes as many as 5 or 6 stitches in a row, and then sews fine again for about 2 dozen stitches. I have removed the bobbin and case and killed all the dust bunnies, checked to make sure the bobbin is in right and it still does it. Unfortunately, the manual is still packed somewhere, if I haven't lost it all together. Any ideas?