My Nordictrack X9i treadmill console says it is operating at speed, however the track is not moving. Occasionally the belt will move for just a moment then it stops.

https://www.livestrong.com/article/410922-the-controls-are-not-working-on-a-nordictrack-treadmill/

Contact Nordic Track directly to inquire about a diagram.

That sounds like the motor is running and the belt is slipping. Can you hear the motor turning? Try adjusting the belt tension.

https://www.google.com/search?q=NordicTrack+C1650

and

https://www.google.com/search?q=nordictrack+c1650+treadmill+troubleshooting

..

Try to lubricate the treadmill running belt.
If you wish to get some details; visit the site linked here. Pull up older posts. http://electro-medical.blogspot.com/

Treadmill walking belt lubrication

Check bewlt for bad bearings/dirt in bearings etc. replace drive belt.

Do you have the iFit component on your treadmill? We had a similar issue and I unplugged the iFit component (requires opening the console and unplugging the ribbon cable that attaches the iFit component) and the treadmill started working again.

You should immediately replace the console. That console will just keep getting worse. This is endemic of this brand, however it usually happens a lot further in the life of the unit. When you call Nordictrack have your model number.

motor controller shorted see me at mc70repairexpert.com

If belt hasn't been replaced that's your poblem. If that's more than you want to put in a 10 year old treadmill, try lubricating it. That may bandaid the problem for a while. This will progressively get worse over time.

If everything on the display console is working correctly then we know it is either a problem with the wires from the console to the controller or the controller itself. In most cases this means you need a new controller. To verify, take off the motor hood and find the green circuit board called the motor controller. With the power on go into manual mode and push the speed up button to a slow speed. If you see an LED light with "spd ctrl" next to it flickering but the belt still does not move then we know the problem is with the controller sending the signal to the walking belt, in which you should check the wires that go to the motor. If they are connected correctly then we know a new controller is in order. If you do not see a flickering light then it means the speed signal never got there and the problem will be with the wires going from the console to the controller. This is called an upright wire harness.