12 mo. ago • 50%

Supermicro PSU yellow light on battery power?

This is a weird thing I have happening on one of my servers, these have been running nearly 7-8 years but I recently swapped a new MB/CPU etc in a server. IT's SC836 dual redundant PSU.

So both PSU are plugged in it's own UPS. When I pull the plug from the wall, the PSU that's on battery will go yellow and scream loud alarm. Mind you other servers are connected to this UPS getting battery powered AC. Only this server does this. I tried it with both PSU and both do the same thing. Is something wrong with the chassis PDU/PMBUS or something else like MB/ram/CPU?

7 comments

Is your UPS a stepped sine wave or a true sine wave?

Does the alarm go away if you completely unplug the other PSU? Does the server keep running if you do or does it shut down?

1
- Simulated sine wave. The weird thing is my 2 other supermicro servers on those UPS don't have that issue, it's just this one.
  
  The alarm is normal, if you unplug 1 PSU it warns that something is wrong. But it shouldn't do that on UPS battery. Server keeps running because other PSU supplies power to server.
  
  1
  
  Some systems don’t like simulated sine waves.
  
  You need to test what happens if you unplug the second PSU because it’s possible the first is shutting down on what it considers an invalid input. You might not actually have any redundancy.
  
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