Power Supply on iTead iBoard

Hi,

I'm using a iTead iBoard for a project. I would like to use an ATX power supply and take the 3.3V to connect with the power connector on the iBoard. I tried this already but it seems that the iBoard will not get any power. It is working perfectly if I use the iTead Foca board as power supply.

I also measured the power output of the ATX power supply and I have 3.401V on it. I have no idea what could be wrong.

Would be happy if someone could give me any advise.

Thanks Alex