I have a 4 yr old ProForm 530i treadmill (2.65 HP motor) that recently has stopped running. The console seems to work properly and the incline as well, but when I set the speed to any non-zero value, the motor starts off very fast and then stops about 3 sec later. I removed the cover and ran it, and noticed that the commutator on the motor arcs quite a bit for those 3 sec. I put the console into debug mode to get more information, but wasn't able to ascertain much. The controller status value starts at 0 (off) then goes to a somewhat random (and undefined value such as 9, 192, or 12 for a moment, then to 1, which is supposed to indicate reset. I don't know if this means that the unit reset it due to current limiting or something, but I never get any error codes. I am presuming that the motor is bad, but I am unsure if this is truly the culprit, not having ever repaired a treadmill. The last month the belt has been slipping a bit, so I did recently tighten the belt slightly (1/4 turn on each side as suggested), but I have not lubricated it in some time. During my testing, I also reduced the tension on the belt so the motor was no longer driving it, but it still only runs for about 3 sec before shutting down. Does anyone have any thoughts on this? It has been very good these last 4 years, 1447 miles and 40 pounds.

Dan McDermet, May 2008

I think your lower board is bad. The lack of lube or a worn belt and deck could cause this.
The motor only goes faster because of the voltage going to the motor. Motors usually don't go bad and go faster. The sparking on the brushes is from the large amount of voltage going to the motor.
The brushes could also be burnt causing increased amps that can blow a lower board.

Also make sure the speed sensor is clean and aligned

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Mark Peterson, May 2008