I've got a little problem. On two machines a power supply LED at the rear near the plug started blinking Orange. The hashing went to zero. From the UI, I tried reboot. Other stuff. Nothing worked. Then I did a power cycle. The machine instantly came back up.
The orange blinking LEDs will be common at first. It indicates a PSU failure of some sort or another. The SP30 is designed to push the PSUs to the point of thermal failure, then remember where that was, and push it slightly less hard next time.
With the Emerson PSUs (everything that's been shipped so far, AFAIK), the PSUs will usually automatically recover after about 20 seconds. Occasionally they don't. I've seen one fail to automatically recover once. In that case, a hard power cycle (unplugging the affected PSU, waiting 30 seconds for it to cool down, then plugging it back in) fixed it. That PSU has had no problems since.