Note, the instructions below are how I diagnosed the problem I describe.  I'm providing it here in case these steps help you narrow down your issue somewhere along the way. I have an Antminer S7 (batch 8) unit that has been giving me problems.  It worked fine for a week or so then started slowing down.  I could hear the fan slowing down and speeding up and if I checked the web GUI of the unit I could see that “chains” 1 and 3 often had very cool temperatures, as if they weren’t even running. It would then try to get those engaged again and it would speed up and then the cycle would repeat.  Eventually, over time, I’d get a high piercing alarm sound and at that point if I checked the GUI I’d see Xs in the ASIC display instead of Os (image below). Above is how it was typically running.  After a while an alarm would sound and it would look like below: PSU: The first things I tried were to swap power supplies with a working unit.  It’s very likely a PSU is sli