The DMC displays force but no deflection during the test. Deflection stays at zero.

There is no information coming from the line counter in the tester. The 9X series testers have an "OPTO DISK" located in the top of the tester. This disk contains lines that are counted as torque bar travel(deflection) and speed. If this disk is dirty or has jumped out alignment there will be no deflection information. Refer to the operator’s manual for disk access or cleaning.