Hello! I own a FlashForge Creator Pro. One of the extruders clicks and does not feed filament thru it. I changed the stepper motor and still the same issue. When I reverse the extruder power cables, the problem duplicates to the other extruder and the other one operates OK. Could this be a bad motherboard? I hate to shotgun parts, especially since the MP is pricey? If it is in fact the MB, who has the best $$ for one? Thanks in advance.