Are you sure that there are no power issues? Maybe you can try a different PSU or a different plug (i.e. the molex connector), or another USB cable, or maybe as the final test un-plug the fan and try if it works.

By the way:
I wish to say "thank you Blackarrow" because -instead of the ATX PSU board I've ordered- I received three PSU with three "splitters" with 4 Icarus plugs each. It's clear that they haven't the board or the needed cables, and they delivered anyway, even if the PSU are more expensive!

Thanks.

Then another (really!) good news are:
- my "kill-a-watt clone" is measuring 23 watts off the wall (way lower than 30!)
- my icarus (other nine are still waiting in their box) is hashing at about 5.80 units/m (diff 1) on 50btc - I'm reading a value >390Mh/s
- the small fans are really silent and the back of the FPGAs are quite cool after 2 hours of hashing, no liquid cooling needed