Gen7 1.5. ATX power supply (1 reply)

I have been running my 1.5 board for quite a while with power just going through the disk connectors. I just bought a new ATX power supply and plugged it in, switched the jumper to ATX. When I turn it on one of the USB LEDs flashes and both the standby and power LEDs come on, when I connect with Repetier host it shuts the power supply down. Any tips on what to check?

Brian