Nortic track c2155 will not propel. computer portion turns on fine but when hitting start nothing happens. i hear no motor sounds or anything. however, the track will move if pushed manually.

Unplug the unit and remove the motor shroud insert plug back in the outlet.The single most cause of no motor output is failure of the DC motor control. Look for any test lights on the power boards beneath the motor hood.If it operates on an open-loop system, the computer will run normally and not give and error code, but the motor will not turn. If you have a multimeter, you can test to make sure you have DC output from the controller spades if not replace the control board. If you have DC output, but motor is not turning the test the motor itself.
Cordless drill battery- get a fully-charged, 18 volt (preferred) cordless drill battery and on most treadmills connect the red and black motor leads to the battery (some have different colors but if you have two wires and get it hooked up backwards, the motor will just run backwards and won’t be harmed). If good, the motor should operate at about 1 MPH.
Car battery- these are 12VDC high amp batteries so the motor will turn slowly but you can walk on the belt. Always be careful with battery acid on these things so we don’t recommend bringing them in the house…take the treadmill to the battery.
Lantern battery- a fully charged lantern battery should operate your motor at a slow speed but lacks the amperage to have someone walk on the belt. If it does not rotate replace motor