well the probability for 2 dead linear regulators is very low I would say. (I have 2 of the power supply doing the same!)
My best bet is that I had a bad wall plug while testing some weeks ago (as everything else seems to improbable to me)
I will buy 2 new netduino go´s and 2 dc-DC converter and see if I am willing to solder .
Does anyone knows the (mouser)part number of the 2.2 uH inductor?
Thanks
br
francesco