see the diagram attached.
Clean the motor, lube the gear+shaft
Adjust the small POT for a little.
RUN the software calibration for troubleshooting. see the diagram
he Steps for Newer Style Console Calibration
1.Locate the calibration area on the rear or underside of the console (a hole, near the console's center, that goes through to the electronics board. (This hole should not have a screw in it.)
2.Insert a pencil (eraser end), into the hole and feel around for the cal button (will click when pressed).
3.Press the button 2 times (with the pencil eraser). The first click should show CL11 in the console, the second click should show CL21.
4.If the process was done correctly, and CL21 appears in the console, you are in "calibration mode." The next few steps consists of pressing buttons on the console and observing settings. This will not require any other tools.
5.Press ENTER. CL22 should display in the TIME window and (??) in the SPEED window.
6.Press ENTER. CL23 should display in the TIME window and (??) in the SPEED window.
7.Press ENTER. CL24 should display in the TIME window and (??) in the SPEED window.
8.Press ENTER. CL25 should display in the TIME window and (??) in the SPEED window.
9.Press ENTER. CL26 should display in the TIME window. You should then see the letter "E."
10.Press ENTER. You should see "SS" or "55" in the console.
11.Push the STOP/START button. For safety, at this point, you should step off, or be off, the treadmill.
12.Push the ENTER button. The walking belt should start to move, accelerate to maximum speed, then stop on its own.
13.When the belt stops, the incline should self test by raising to its highest incline position, then lowering back down to its lowest position.
14.Once the incline test is complete, push the POWER button 2 times. The unit should shut off and the console should go completely blank. If this happens, the treadmill is done calibrating and is ready for use.
15.If the letter "F" appears in the SPEED or INCLINE window when the power button is pressed 2 times, the treadmill is indicating a failure somewhere either in the SPEED or INCLINE (depending on the window the "F" appeared in). Troubleshooting the failure would be the next step.
God bless you