Pfaff 919 Owner's Manual - Page 72

Faults and how to remedy them Cause: Remedy: 1. Machine skips stitches Needle not inserted correctly. Wrong needle used. Needle bent or blunt. Machine threaded improperly. Needle too thin for thread used. Push needle up as far as it will go, its flat shank side facing rear. Insert system 130/705 H needle. Insert new needle. Check threading. Use thicker needle. 2. Needle thread breaks For any of the above reasons. Thread tension too high. Poor-quality or knotty thread used, or thread that has become too dry by excessive storage. See par. 1 above. Regulate thread tension. Use only good quality thread. 3. Needle breaks Needle not pushed up as far as it will go. Needle bent. Needle too thin or too thick. Needle bent and strikes needle plate because workpiece is pushed or pulled. Bobbin case improperly inserted. Insert new needle and push it up as far as it will go. Insert new needle. See Needle Chart. Let machine feed the workpiece. Only guide the material lightly. When inserting the bobbin case, push it in as far as it will go. 4. Seam is not uniform Tension out of adjustment. Thread too thick, knotty or hard. Bobbin thread wound unevenly. Kinks appear on top and bottom of material. Check upper and lower tensions. Use first-class thread only. During bobbin winding, do not hold thread in hand, but pass it through the bobbin winding tension, Thread machine properly and check both tensions. )