unscrew the cover underneath the display board and you will see the slot where the key should be inserted. On the side there is a metal blade that should be pushed aside by the key to come in contact with the side and complete the circuit. Any thing that pushes it will make the treadmill work either put some plastic in place of the key to fit in its place and hold the blade to the side or stick the blade somehow... hope this helps
RYH, December 2008
