Ensure that the thread tube or tension device is not touching the hooks when they are out. The hooks may be loose or their top position may be too low. Thread tube may have become distorted and may need bending back to shape. Two different motors have been fitted to the Mk 18 and the software needs setting up correctly for motor type on the machine. When the machine is powered up the software number is displayed with either M or G after it. M motor type is 26 mm diameter and G motor is a smaller 22mm diameter. Consult MMS for details of how to change this option in the software.