Trying calibrating the speed on your machine. You can watch
to see the procedure for this.
Also, you may try checking the walking belt tension as well as the drive belt tension. You can watch
to see the procedure for the walking belt tension adjustments.
If neither of these situations seems to correct the problem then it's most likely going to be the controller failing on your machine. You can check the motor with a volt meter to see if it's failing but I have a feeling it's fine. To check the motor: Remove the red and black power leads from the motor at the controller. Then connect the meter to those leads (meter connected to motor). Set the meter to read DC voltage. Put the safety key in place and then walk on the treadmill (manually, do not press any keys) up to 3mph. At 3mph the meter should read 28VDC or more. If it's less than that the motor has failed. If the voltage is 28VDC or better then the motor is fine and just the controller will be the issue. If the motor does check out bad, I would replace the motor and controller as a set.
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