After building 10 printers for friends and family I've ran into a problem I've not seen before. When I turn on either hot end or bed I see the spike on the ponterface display showing and within a second or two the graph flatlines. A check of the voltages indicates 0 vdc.at the hot end and bed connectors, but full voltage at the power supply connectors. So far I've swapped out the Mega and the Ramps boards and the power supplies. The firmware is the same as I'm running on other printers including my own.
Anybody have any suggestions?