The "ASIC status" on some of my 400M overclocked Antminers show all x's (i.e., xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx) yet the temps are fine (~44-46) and the hashrate is still showing about 200 GH/s, as well as hashrate on my pool staying the same. Is this a warning that I'm slowly burning out the unit?
From what I have read "x" means either not enough power to the chip or overheating.
Since the machine is overclocked and pulling more power, perhaps you are on the cusp of the power range of you PSU?
Do you have a Kill-a-watt (or other such device) to measure what the S1 is pulling at the wall?
6. I see "x" in the ASIC Status
For the ASIC status wise, "x" doesn't necessary means the chip is faulty or failing. If the hashing power seems to be affected, please check your PSU and wiring and reboot and check the status a few times. It should go back to an average 168-180 gh/s range per AntMiner.
when you are getting "x" on the ASIC chip status, please turn off the antminer and double check your PSU cables are connected well and restart. Check the status in about 5 minutes and every 30 minutes for a few hours and see if the "x" are showing up constantly at the same chip or randomly changes or completely disappear.
src:
https://bitcointalk.org/index.php?topic=344970.0