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 125 for information on logging onto the IMM web interface.v Ethernet activity LEDs: When any of these LEDs is lit, they indicate that theserver is transmitting to or receiving signals from the Ethernet LAN that isconnected to the Ethernet port that corresponds to that LED.v System-locator button/LED: Use this blue LED to visually locate the serveramong other servers. This LED is also used as a presence detection button. Youcan use IBM Systems Director to light this LED remotely. This LED is controlledby the IMM. When you press the System-locator button, the LED will blink andit will continue to blink until you press it again to turn it off. The locator buttonis pressed to visually locate the server among the others servers.v System-information LED: When this amber LED is lit, it indicates that anoncritical event has occurred. Check the error log for additional information.v System-error LED: When this amber LED is lit, it indicates that a system errorhas occurred. A system-error LED is also on the rear of the server. An LED onthe light path diagnostics panel on the operator information panel is also lit tohelp isolate the error. This LED is controlled by the IMM.v Hard drive activity LED: When this green LED is lit, it indicates that one of thehard disk drives is in use.Notes:1. For a SAS drive, a hard disk drive activity LED is shown in two places: onthe hard disk drive and on the operator information panel.2. For a SATA drive, hard disk drive activity is indicated only by the hard diskdrive activity LED on the operator information panel.Light path diagnostics panelThe light path diagnostics panel is located on the top of the operator informationpanel.Note: The system service label on the underside of the cover also providesinformation about the location of the light path diagnostics LEDs.To access the light path diagnostics panel, slide the blue release latch on theoperator panel to the left. Pull forward on the panel until the hinge of the operatorpanel is free of the server chassis. Then pull down on the panel, so that you canview the light path diagnostics panel information.Note: When you slide the light path diagnostics panel out of the server to checkthe LEDs or checkpoint codes, do not run the server continuously with light pathdiagnostics panel outside of the server. The panel should only be outside of theserver a short time. The light path diagnostics panel must remain in the serverwhen the server is running to ensure proper cooling.18 IBM System x3550 M3 Type 4254 and 7944: Installation and User's Guide
