Hello, I have a Nordic Track 2050, and got on this

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

SORRY BUT THIS IS NOT NORDIC TRACK TECH SUPPORT

The motor controller board is faulty.
If you wish to get some details; visit the site linked here. Pull up older posts. http://electro-medical.blogspot.com/

Motor control board replacement is essential !

this happen to due the lack of maintenance according the schedule manintenance. see the video and proceed.However if after you did, the problem remain,is TIME to replace the old board deck. God bless you

adjust the speed sensor, see the diagram attached. clean it and test it for open or faulty. Tight the connector very well.RUN the software calibration for easy diagnose, and fix it. God bless you

Remove the console from the treadmill and remove the back
remove and replace the ribbon cables that run from the keypads to the control board (they are flat plastic strips that push into the board).
remove and replace all the connections on the console
reattach the console and calibrate by doing the following:
1. With the key off press the speed + and stop buttons at the same time and hold
2. place the key on and release the buttons
3. press the stop key once
4. press the speed up til it reaches 85
5. if your max speed is 10 mph then it should read about 9.8-10.2

If the keys will not work then the console is bad and would need replaced.

go to iconservice.com click on manual input this info Nordic Track THEN Model name 2050 these 12 matches for that unit.

You should have a speed arrow up & down, this increases and decreases the speed in .1 mph. Try this control and see how the unit re-acts if the speed does not adjust in .1 mph increments or it stay the same either way it sounds like an upper board issue. Go to iconfitness.com go to customer service the replacement parts put you M# and will give part# and pricing.
RULE OF THUMB: IF REPAIR IS MORE THAN THE THE PURCHASE PRICE OF UNIT DOE NOT REPAIR

Is there a sheet of paper under the motor hood? It has the procedures for this calibration of the motor speed. Caution ! You should use a plastic screwdriver to make adjustment to the speed control on the motor controller. It is high voltage