IBM 8874 - eServer xSeries MXE 460 Installation Manual

Contents

Light path diagnosticsLight path diagnostics is a system of LEDs on various external and internalcomponents of the server. When an error occurs, LEDs are lit throughout theserver. By viewing the LEDs in a particular order, you can often identify the sourceof the error.The server is designed so that LEDs remain lit when the server is connected to anac power source but is not turned on, provided that the power supply is operatingcorrectly. This feature helps you to isolate the problem when the operating systemis shut down.Any PCI-X, memory, microprocessor, and VRM LED can be lit again without acpower after you remove the microprocessor tray so that you can isolate a problem.After ac power has been removed from the server, power remains available tothese LEDs for up to 24 hours.To view the PCI-X, memory, microprocessor, and VRM LEDs, press and hold thelight-path-diagnostics button on the PCI-X board, memory card, or microprocessorboard for 30 seconds to light the error LEDs.The LEDs that were lit while the server was running will be lit again while the buttonis pressed.Many errors are first indicated by a lit information LED or system-error LED on theoperator information panel on the front of the server. If one or both of these LEDsare lit, one or more LEDs elsewhere in the server might also be lit and can directyou to the source of the error.Before working inside the server to view light path diagnostics LEDs, read thesafety information that begins on page v and “Handling static-sensitive devices” onpage 8.If an error occurs, view the light path diagnostics LEDs in the following order:1. Check the operator information panel on the front of the server.v If the information LED is lit, it indicates that information about a suboptimalcondition in the server is available in the BMC log or in the system-error log.Important: If the server has a baseboard management controller, clear theBMC log and system-event log after you resolve all conditions. This will turnoff the information LED and LOG LED, if all conditions are resolved.v If the system-error LED is lit, it indicates that an error has occurred; go tostep 2 on page 75.The following illustration shows the operator information panel.Power-control buttonPower-on LEDUSB connectorHard disk drive activity LEDInformation LEDSystem-error LEDLocator LEDRelease latch74 IBM ERserver xSeries 460 Type 8872 and xSeries MXE 460 Type 8874: Installation Guide