Smartcraft power is from the engine's electrical harness. Most late engine arrangements have a 14 pin round connector which is the Smartcraft primary connector; from that connector are the 10 pin square Smartcraft connectors. Two of those pins are the network's power. Specifically where that power is sourced on the engine? I don't know but there is always a fuse.If I follow what Tom says and look at the videos....it would appear that you are losing power on the Red and Black wires which in turn causes the display to turn on and off.
Can you put a voltmeter on the red/black wires and see if power drops?
Tom, where is the power supply for his Smartcraft system and what voltage should he see on those wires?