The readings should show '0.00' for the normal state and '1' for the depressed state. Check the readings with the switch depressed and in its normal state. Put each probe on each of the switch terminals.
If the readings are as above, then the limit switch is working. The reading should show '1' with the switch in its default position and '0.00' when the switch has been depressed.
Please refer to the tutorial below by ifixit on how to use a multimeter before proceeding with the steps below. The measurement should be identical to measuring from corner B to corner C. For example, measure from corner of end plate A to corner of end plate D. An assistant is recommended to get accurate results. Both diagonal measurements must be identical. Ensure that your machine is square by checking the diagonal distance as shown below.Spray your lead screw with PTFE lubricant and run the machine back and forth a few times.Slightly tighten them and then move the machine to the back and fully tighten them.
Loosen the nut blocks a full turn or until there is a slight movement from the nut block. Please contact us at Adjust your nut blocks. Remove the lead screw from the machine and roll it on a flat surface like a garage floor or marble bench top. If your machine is lead screw driven, check the lead screw for bends.
The wheels should be easy to move with a little bit of force. It should be smooth throughout the length of the gantry. Remove the lead screw and move the gantry by hand. Try to stall the motor by applying pressure to the motor coupling by hand.
If the bench test passes, there may be mechanical, electrical or software issues putting extra stress on the motor.