Got the blade but it seems broken, it shows all "x" in Chip status

Make sure you have a sufficient power supply.
Tried with a 500W and a single rail 750W, all "x"

I have an HX 750 running a blade and 2 60 GH/s singles Kill-a-watt says 616W at the wall (with netbook host).
So you probably have enough power. How did you wire the power? Follow dogie's post? I would check the voltage going in with a DMM. Should be around 12.2~12.5 depending on power supply.