by RetireeJay » 2015-Jan-Thu-07-Jan
Actually, if you do not have a heated bed, then the connector for the heated bed does have continuous +12V. (It switches the ground on and off to control the heat.)
Ground can be found at any of several places. However, the easiest ground to pick up will be different depending on whether you have a Rev D or a Rev F board.
This seems to be such a common issue that I think Printrbot (or somebody) should offer a pre-built assembly with the barrel connector, the ATX-style plug for the board, and a fan plug already spliced in.
Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3, upgraded to MK3S