I recently had an issue with my M505 prusa I3 where I had to connect it to another pc. Once I moved the printer and starting printing again I noticed that during the print the extruder motor is not moving to pull the filament. I test the extruder in repetier manual control and the motor works to pull the filament fine. I am not sure if any settings have changed or if the board is the issue.

Thanks,

Keith

Make sure your thermistor is still reading correctly and check that your control software didn't switch from relative coordinates to absolute or vice versa.