It turns on and I can hear the motor running but the tread does not move.

Question edited for clarity and what the make and model actually is.

This is likely to be the Start / Run Capacitor on the motor. It gives the motor and electrical jolt and ten keeps it running.

https://manualzz.com/doc/1740950/proform-crosswalk-831.297231-owner-s-manual

https://www.google.com/search?q=proform+831+motor+humming

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The mechanical link from the motor to the tread belt is likely broken. From the sound you describe, there could be a drive belt that needs replacing or maybe a pulley wheel.

could be that your drive belt is broken. if you hear the motor running. you will need to remove the cover on the front of the treadmill to see

You have the belt on wrong. There is a side with numbers or writing on it and ribbed side like treads. The tread side should be facing down, making contact with the drum. If the other side is touching the drum then whenever clothes are put in the belt will slip causing the drum not to turn.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/jason_4570d45317834dd3

Drive belt may not have adequate tension, motor brushes may be worn out, tread tension may be too tight, one or more of the control devices may have failed, the power to the treadmill is inadequate.

Drive belt can be viewed with the motor cover removed. If it slips, adjust tension until static belt delfection is about 1/8 inch.

If motor halts with load and belt does not slip, adjust the tread tension by turning the track tension bolts counter clockwise 1/4 turn at a time, both adjusters evenly. If no improvement 1 full turn in, check motor and or control board.

if tread adjustment does not help, check the brushes to make sure they are not hanging up in the holder. Remove the plastic caps that retain the brush inthe motor with treadmill unplugged, If they are 1/4 inch in length or shorter- replace brushes. If the motor does not have brushes, it is an AC type motor.

If brushes are fine, check motor voltage with an analog voltmeter- AC range if you have the open frame AC type of motor where you can see the windings (no brushes) and measure voltage on theboard terminals that go to motor. They should adjust from zero to at least 80 volts via the speed control knob. If the AC motor hums a great deal, replace the motor run capacitor.

If you have the DC motor, (usually about the size of a 1 liter bottle.), Check voltage range, it should have the same voltage range as above with meter set to DC range.

If in either case the motor moves fine, but full speed on control does not yield full motor speed, check the devices, usually SCR or Triacs on the AC motor type and MOSFETS or IGBT on the DC motor types.

Treadmills are usually made up of various components. The rolling surface (tread) is usually placed on a set of rollers when the unit starts due to the low friction between both the surface (tread) and the rollers the surface (tread) starts slowly while the rollers move regularly and the sensor is placed on the movement of the rollers.
What you need to do is get the unit serviced usually there is a way the tread it tightened to have better grip on the rollers. This method differs from one make to the other so get an expert who knows about proform rollers. Once the system is tightened the problem will be solved.
Hope this solution has been helpful?

The motor must move the drive pulley for calibration to pass. remove rear covers and check drive belt. you should hear the lwr board relay click to engage the motor. if you hear it and the motor does not move and you have checked the belt then you need to test the motor. Typically remove the belt and turn by hand...it should be very smooth and spin freely. If not replace the motor. Direct 9 volts to the motor leads unplugged from the board will tell you if the motor is good. be careful as capacitors are present and risk of shock is always possible. capacitors stay charged for about 10 mins after unit is unplugged

Make sure treadmill is running when you adjust belt. The treadmill belt tracks as the belt goes around. I usually put machine on 2-2.5 if belt is not rubbing instantly. If belt is already against plastic, turn adj. counterclockwise on the opposite side about one full turn. You can usually move belt with your foot to see if it aligns any with turning on the treadmill. Once belt is not rubbing, turn treadmill on and continue alighing the belt.

DEAR
AT FIRST YOUR MOTOR CONTROL BOARD IS DAMAGE
I can turn it by hand it turns smoothly and the tread moves fine and the belt from the motor to the tread is good

I'd start by attaching a voltmeter across the motor contacts to see if you get any voltage when the unit is turned on. It's probably an AC motor but I'd check the label to be sure. If you get voltage but no turning either the motor or a startup capacitor is bad. If this is the case try moving the tread by hand with the unit turned on. If it moves on it's own after you start it moving then the start up cap needs to be replaced. Otherwise it may be time to replace the motor. If you don't have voltage across the motor contacts when the machine is turned on, I'd unplug the unit and trace the lines back from the motor to somewhere on the PC board. I'm guessing there's probably a relay on the PC board that controls the motor. I'd use an ohm meter to make sure the relay coil hasn't turned into an open circuit. Next I'd put a voltmeter across the relay coil, plug the unit back in, and turn the treadmill on and off several times. Ideally you should see the voltage across the relay coil go up and down as you turn the treadmill on and off. This voltage could be AC or DC depending on the type of relay used. If you get the proper voltage across the coil but the relay contacts aren’t' opening and closing to provide power to the motor then you need to replace the relay. If you don't get the proper voltage across the relay coil the problem is further back on the PC board.