Resistance Level Will Not Change On My Nordic Track Sl720

Hello there, The calibration mode for a nordictrack is as follows.

With the safety key out, hold the stop and speed up arrow at the same time while inserting the key. Release the buttons. You will then be in diagnostics.
You then press the stop button one time.
If you are trying to calibrate the incline you just need to hit the incline up button and the machine will do an incline calibration. The unit should go all the way to the top and return to the bottom when completed.

If you need to calibrate the speed you will need to press and hold the speed up button on the console until the display reads 85. The machine should then be running at its maximum speed (either 10 or 12 mph depending on the unit)
The display will show a speed on the console and should be within .3 of the maximum speed.
If it is not then it will need to be adjusted using a potentiometer on the control pwb.
To access the control pwb open the hood cover. Should be 3 screws in the rear of the cover and 2 screws on the bottom of the unit.
Once inside the cover locate the control pwb. On the control pwb there will be a yellow/orange potentiometer. This is the adjusting part.
Use a non-metallic phillips head screw driver to adjust the potentiometer either clockwise for faster or counterclockwise for slower.