Please reduce the board frequency to 487.
If the issue is not solved Please try reloading the firmware:
Run the miner for 20 minutes after loading.
Please first check the PSU and the controller. To check the PSU you can test the machine with a known good PSU. If you do not have another PSU then check by switching the cables between hash boards. If the issue follows the cable then the PSU may be faulty. Please reply to this email for more instructions.
To test the controller, switch the controller cables between hash boards. If the same hash board shows the issue then the hash board is faulty. If the issue follows the cable then the controller may be faulty. Please contact us for further instructions.
If it still is not solved please test each hash board separately to determine which one is defective.
To test each hash board separately: keep the PSU connectors and controller cable on one of the hash boards connected and disconnect the cables from the other two hash boards. With the miner running you can see the status of the connected hash board.
Here is more detail: http://support.bitmain.com/hc/en-us/articles/226142788-Testing-hash-board-one-by-one
On the miner status screen defective chips are displayed as "xxx", "---" or " ASIC≠60
Once you know which part is defective please create a Repair ticket and ship the part back to us according to these instructions: https://shop.bitmain.com/repairGuide
Please pack the hash boards carefully. If the PINs are lost due to shipping damage it will void the warranty. Here is a video demonstrating how to pack the boards: https://youtu.be/Z0LdykALhxI
You may disassemble the miner and break the warranty seal under the instructions from this article.