I am having a similar issue with one of my miners. I received 8 S3 units, but one of them is running the fans at full speed but failing to hash. I can connect to it and alter settings, but I cannot get it to start hashing. I have switched PSU's, network cables, factory reset it, reinstalled the firmware, reset it from settings I saved from another miner, and I have taken it apart to check all of the connections.

The Antminer S3 is showing a solid red light and the fans are running at full speed. What is going on with this unit?? All of the other 7 are working perfectly on their own static IP addresses.

Oh, and it is also restarting itself every three minutes. I know this because if I look at the "elapsed" time under miner status it never passes three minutes. Please help!