Just assembled an mbot3d cube kit plywood version. Tried the utilities option to home all axes and it send the z-axis to the bottom, I ignored it thinking the utility might be defected, but even printing anything is doing the same thing and hence all prints are up in the air (useless). Can anyone please help me in this regard? Also I am using a Mac and ReplicatorG is not finding the printer directly hence I can not upgrade the firmware either if there is anyway to do this via the SD card? Thank you.
It sounds like you may have your Z axis stop connected wrong. The X and Y axis stops are connected to the max connections on your control board. The Z axis stop should be connected to the Min axis connection.
Actually it turned out to be a faulty stepper driver, when I swapped the Z and X drivers, X stopped working. Luckily I have the dual extruder model so at the sacrifice of the second extruder, I can print properly. I am trying to get a spare driver but the store is confusing about old and new drivers and I am not sure which ones are shipped with the kit I got. So for now its single extrusion 
