the power supply is supplying adequate dc power to the system. During typicaloperation, both the IN OK and OUT OK power LEDs are lit. For any othercombination of LEDs, see “Power-supply LEDs” on page 110.v Power-supply error LED: When the power-supply error LED is lit, it indicatesthat the power supply has failed.Note: Power supply 1 is the default/primary power supply. If power supply 1fails, you must replace the power supply immediately.v System-error LED: When this LED is lit, it indicates that a system error hasoccurred. An LED on the light path diagnostics panel is also lit to help isolate theerror.v Power-on LED: When this LED is lit and not flashing, it indicates that the serveris turned on. The states of the power-on LED are as follows:Off: Power is not present, or the power supply or the LED itself has failed.Flashing rapidly (4 times per second): The server is turned off and is notready to be turned on. The power-control button is disabled. This will lastapproximately 20 to 40 seconds.Flashing slowly (once per second): The server is turned off and is ready tobe turned on. You can press the power-control button to turn on the server.Lit: The server is turned on.Fading on and off: The server is in a reduced-power state. To wake theserver, press the power-control button or use the IMM Web interface. See“Logging on to the Web interface” on page 268 for information on logging onto the IMM Web interface.v System-locator LED: Use this LED to visually locate the server among otherservers. You can use IBM Systems Director to light this LED remotely.Server power featuresWhen the server is connected to a power source but is not turned on, the operatingsystem does not run, and all core logic except for the service processor (theintegrated management module) is shut down; however, the server can respond torequests from the service processor, such as a remote request to turn on theserver. The power-on LED flashes to indicate that the server is connected to apower source but is not turned on.Turning on the serverApproximately 5 seconds after the server is connected to power, one or more fansmight start running to provide cooling while the server is connected to power andthe power-on button LED will blink quickly. Approximately 20 to 40 seconds after theserver is connected to power, the power-control button becomes active (thepower-on LED will blink slowly), and one or more fans might start running to providecooling while the server is connected to power. You can turn on the server bypressing the power-control button.The server can also be turned on in any of the following ways:v If a power failure occurs while the server is turned on, the server will restartautomatically when power is restored.v If your operating system supports the Wake on LAN feature, the Wake on LANfeature can turn on the server.Note: When 4 GB or more of memory (physical or logical) is installed, somememory is reserved for various system resources and is unavailable to the14 IBM System x3550 M3 Types 4254 and 7944: Problem Determination and Service Guide
