Ken Evans

Q: Reset PMU Xserve

Got an XServe intel version. Trying to reset the PMU as the fans have gone crazy. Had an engineer look at it, given the all clear but the instructions we've found are not at all clear and don't actually make sense.

*+1. In order to enter the headless command mode, hold the identifier button while you power the Xserve on.+*

*+2. Keep pressing the identifier until you see the top row of blue lights on the Xserve blinking.+*

*+3. Stop pressing the identifier button. You'll notice that the right-most blue LED on the bottom row is lit up - this indicates that the system will start from the system disk.+*

*+4. At this point you can press the system identifier button in order to cycle through the boot options. They are as follows (right to left)+*
*+- System Disk+*
*+- Network Boot+*
*+- Start from leftmost drive+*
*+- Boot next disk (other than startup disk)+*
*+- Target Boot Mode+*
*+- Reset PMU+*

*+5. Release the button once again and the system will boot into your desired mode.+*

We can get it to the 4th step and light up the PMU reset light but we would have already released the button to select that option! It then just sists there and doesn't reboot. If you power down and restart it starts normally again!

Any ideas? (Can't reset on MB as we can't access the server without serious surgery in the cabinet, it's not on rails)

Thanks.

24" iMac, 17" Mac Book Pro, Mac Pro Quad Intel Dual Core, Mac OS X (10.5.6), Infortrend 20TB RAID - ATTO Fibre Channel - FCP Certified Pro Trainer

Posted on Feb 10, 2011 7:35 AM

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Q: Reset PMU Xserve

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  • by ClassicII,Helpful

    ClassicII ClassicII Feb 10, 2011 10:24 AM in response to Ken Evans
    Level 3 (835 points)
    Feb 10, 2011 10:24 AM in response to Ken Evans
    Hey Ken,

    If you are looking to reset the pram or nvram you can do so with sever monitor on a remote machine.

    In server monitor you can click on the restart button and then select "on the next restart" Reset NVRAM and then select the first bootable drive.



    It sounds more the like the system management controller is what you are looking for though as it controls the fans.

    Follow these instructions for tha

    1. Shut down the computer.
    2. Unplug the computer's power cord.
    3. Press and hold the power button for 5 seconds.
    4. Release the power button.
    5. Attach the computers power cable.
    6. Press the power button to turn on the computer.
  • by Camelot,

    Camelot Camelot Feb 10, 2011 10:58 AM in response to Ken Evans
    Level 8 (47,285 points)
    Mac OS X
    Feb 10, 2011 10:58 AM in response to Ken Evans
    The instructions are missing a step.

    Once you've pressed the button to advance to the boot option you want, you then press and hold the SystemID button. After about 2 seconds of holding the blue LEDs will fill in. Once they're all lit you can advance to step 5 (release the button to boot the system).