Neptune trouble shooting guide out now:
http://forum.kncminer.com/forum/main-category/hardware/48166-neptune-troubleshooting-guideRidiculous procedure to make up for knc's lack of testing.
And hilariously, the 6 steps lead you to hash at full speed to incorrect pool

1. Disconnect all ASIC boards
2. Power on the miner with only the controller board. Once in the GUI, change your pool details to something that is incorrect ( Yes, that is right, since we do not want the ASIC boards to hash at this moment but we still need access to control the ASIC boards)
3.Power down the miner, then re-connect your ASIC boards.
4. Access the GUI and navigate to the advanced tab, once you are here you should change the clock frequency from 450MHz to 50MHz.
5. Finally, gradually increase the clock frequency in increments every few minutes until you reach 450MHz.
6. Your PSU will then work correctly while your miner hashes at full sp
FUD Alert. The 6 steps are only required if you choose certain PSUs eg. Corsair 1200. The steps are not normally necessary with single rail PSUs, eg. good choice is EVGA 1300W G2 Supernova.