Thanks again for all your help. Time to learn about power and speed settings...
Yet more information:
I flashed it with BenBox with the same results. I can connect to it via the serial port and it reports "benbox laser 3.1(c) mul 2015.06.06" and I can send it Gcode and get 'ok' back so, again, it thinks everythings ok.
Have I got a bad mainboard?
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