PxT

Further discussion here: http://www.printrbottalk.com/forum/viewtopic.php?f=21&t=10508&p=67897&hilit=fan+mosfet#p67897

Not sure if anyone from the Printrbot side is following this, but the upstream bug (moved to https://github.com/MarlinFirmware/Marlin/issues/732) concluded that this is a misconfiguration. The default values for the *_PROBE_BED_POSITION...