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I have a Sun X4100 with dual power supplies. The "rear PSU" LED comes on after the system is powered on and has gone through the self-test. Both power supplies are working just fine -- I can take out either power cable and the system will still have power. Both LEDs on the PSUs themselves are green. The BIOS have no entries in either logs and nothing is displayed on screen at any time prior to loading Solaris.

I'm running Solaris 11 on this system and "prtdiag -v" reports no PSU related info. "fmadm faulty" reports no failures either. "dmesg" has no power-related messages.

I'm stumped as to why the LED is coming on. I've checked the LEDs on the motherboard as well, but there are no indications (lit LEDs) that indicate CPU failure or "voltage irregularities".

What can cause this and is there anything I can do to troubleshoot the situation?

kaared
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3 Answers3

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I had a similar problem on 4 servers ( X4100 M2) brought in by my customers. The front warning light indicating a power issue would not go away, with known good power supplies. The answer above did the trick. Going into ALOM and entering show /SP/logs/event/list showed me what the issue was. Changing the Bios battery on all 4 units made the error go away. Although the Bios was holding the settings the bios battery was too low. This may not work in every case but it is something to look at.

Tim
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    After having several X4100s disconnected from power for a long period, I had the same issue. Thanks for posting this! The item in the event log is referring to low voltage on `mb.v_bat`, which is the 3V button battery, known as the RTC battery. I was originally confused because both rear PSUs were reading `PWROK` "State Deasserted" (not ok) until I replaced the button battery... – 700 Software May 17 '16 at 20:24
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I would check the logs before clearing them in case it is a legitimate issue:

show /SP/logs/event/list

The LED will be lit due to any changes with the PSU - such as voltage or fan speed. If that's not the case usually, you will just need to go into the ILOM and clear the event log.

Easiest way is to go to the IP of the SC or CMM then System Monitoring --> Event Logs --> Clear Event Log.

colealtdelete
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This happens to me all the time. It'll be months before I remember the morons at Sun turn that led on when the CMOS battery is out-of-spec. Unless you hunt through the sensor readings -- and why would you with a "PSU Fault" indicated -- there's zero other indication. Any other PC or server halts to boot process to tell you the CMOS battery is dead. (also annoying.)

-> show -d properties /SYS/MB/V_BAT
  /SYS/MB/V_BAT
    Properties:
        type = Voltage
        class = Threshold Sensor
        value = 0.656 Volts
        ^^^^^^^^^^^^^^^^^^^
        upper_nonrecov_threshold = 3.79 Volts
        upper_critical_threshold = 3.60 Volts
        upper_noncritical_threshold = 3.39 Volts
        lower_noncritical_threshold = 2.69 Volts
        lower_critical_threshold = 2.59 Volts
        lower_nonrecov_threshold = 2.40 Volts
Ricky
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