Pfaff 72 Owner's Manual - Page 25

3. Needle Breaks Cause Bent needle strikes point of sewing hook. Needle too thin or thread too heavy. Fabric pulls needle so it bends and strikes needle plate. Bobbin case inserted incorrectly. 4. Faulty Stitch Formation Cause: Improper tension. Thread too heavy, knotty or hard. Bobbin unevenly wound. Pieces of thread between tension discs. 5. Machine Feeds Improperly Cause: Feed dog dropped. Machine does not feed because stitch length control set on "0". Accumulations of lint packed between feed teeth. Remedy: Replace needle at once to prevent further damage. Use correct needle and thread sizes. Don't force the feeding motion. Guide the material lightly. Push bobbin case until you hear it snap into place. Remedy: Adjust tensions as instructed. Use only first-rate thread - the correct size for the needle and fabric. Don't run thread over finger when winding the bobbin (see page 9.) Raise presser bar lifter and remove thread. Remedy: Raise feed dog (see page 20). Regulate stitch length, as desired. Take off needle plate and remove lint with a stiff brush. 26