Upgrading Your Server 9-17Replacing a Failing Power Supply UnitReplace only a failing power supply unit.IMPORTANT: Do not remove a power supply unit operatingnormally.NOTE: If one power supply unit fails while the server contains twopower supply units in a redundant configuration, the failing powersupply unit can be replaced with the system operating (power-on state).(Skip step 2.)1. Locate the failing power supply unit by the AC POWER LED on the rear of each powersupply unit. (The LED of the failing power supply unit is amber.)2. Shutdown the system, and press the POWER switch to turn off the power.3. Disconnect the power cord from the failed power supply.4. Hold the handle of the failing power supply.5. While pressing the lever, pull the power supply to remove if from the chassis.216. If operating the server with a single power supply unit without installing a new one, installthe cover you removed in step 3 of installation procedure.IMPORTANT: To maintain the cooling effect in the server, install theblank cover in the vacant slot.7. Install the new power supply unit taking steps 4 to 8 of "Installation", and confirm that thepower supply unit is installed normally.NOTE: If one of the two power supply units of the server is replacedwhile the power is on, the POWER LED of the new power supply unitgoes on. (If it is replaced while the power is off, the LED flashes. TheLED goes on when the power is turned on.)