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Solving power problems

Use this information to solve power problems.

Power problems can be difficult to solve. For example, a short circuit can exist anywhere on any of the power distribution buses. Usually, a short circuit will cause the power subsystem to shut down because of an overcurrent condition. To diagnose a power problem, use the following general procedure:

  1. Turn off the server and disconnect all ac power cords.
  2. Check for loose cables in the power subsystem. Also check for short circuits, for example, if a loose screw is causing a short circuit on a circuit board.
  3. If the Check-log LED on the operator information panel is lit, complete the following steps:
    • Check the IMM2 event log. To access the web interface, see Logging on to the Web interface.
    • If a log indicates that there is a power rail failure, find the location of the failed power rail on the power paddle card.
    • Disconnect the cables and power cords to all internal and external devices (see Internal Cable Routing and Connectors). Leave the power-supply cords connected.
    • Remove each component that is associated with the failed power component, one at a time, restarting the server each time, until the cause of the failure is identified.
      Table 1. Components associated with power rail error
      Pwr rail error in the IMM2 event logComponents
      Pwr rail 1 error
      1. For the hot-swap power-supplie systems: Fan 3, optional PCI adapter at Slot 4, and other optional PCI adapters.
      2. For the fixed power-supplie systems: Fan 3, optional PCI adapter at Slot 4, other optional PCI adapters, Hard disk drives, and Optional DVD or Tape drive.
      Pwr rail 2 errorFan 1, Fan 2, and Microprocessor 1
      Pwr rail 3 errorMicroprocessor 2
      Pwr rail 4 errorFan 4, and DIMMs 1 through 12
      Pwr rail 5 errorFor the hot-swap power-supplie systems: Hard disk drives, hard disk drive backplane assembly, and optional DVD or Tape drive.
    • Replace the identified component.
  4. Reconnect all power cords and turn on the server. If the server starts successfully, replace the adapters and devices one at a time until the problem is isolated.
  5. Remove the adapters and disconnect the cables and power cords to all internal and external devices until the server is at the minimum configuration that is required for the server to start (see Server controls, LEDs, and power for the minimum configuration.)
  6. Reconnect all ac power cords and turn on the server. If the server starts successfully, reseat the adapters and devices one at a time until the problem is isolated.

If the server does not start from the minimum configuration, see Server controls, LEDs, and power to replace the components in the minimum configuration one at a time until the problem is isolated.