Anyone have a @Printrbot Rev D compatible firmware that keeps the Z axis powered all the time? I’ve upgraded the threaded rod and now the lack of hold on the Z-axis is causing the weight of the arm to unwind down and pancake/flatten my prints.
This board’s been running great for years - it came with the laser cut plywood and fishing line model! I think only the board, steppers and end stop switches are still OEM. Everything else has been replaced/printed/upgraded 
Change DEFAULT_STEPPER_DEACTIVE_TIME in configuration_adv.h to 0
You use 2mm lead or 8mm lead screw?
2mm
@Alex_Wiebe surprised 2mm is losing travel, that should be self-locking.
It has a brass, not plastic nut, and I’ve lubricated the shaft recently. So, yeah, any vibration and the Z starts settling down.
My bad - got my thread details mixed up. It’s an 8mm lead.
@Alex_Wiebe whoops, there you go. 8mm is not automatically self-locking.
The recompile-upload-firmware rabbit hole got too deep. So I added a 2nd nut squishing a spring with a zip tie. Night and day difference.
missing/deleted image from Google+
missing/deleted image from Google+