1. Insert the four tabs on the fan bracket into the mounting holes in the back panel and slide the fan assembly downward about 1 cm (0.5 inch) until thefan bracket release tab snaps into place.2. Connect the fan power cable to the fan power connector on the system board.To identify system board connectors, see Figure A-3.3. Stand the system upright.4. Install the cover (see "Installing the Cover" in "Troubleshooting Your System").5. Reconnect the system to its electrical outlet and turn the system on, including any attached peripherals.Redundant Power SuppliesThe optional redundant power supplies are accessible from the back panel.Removing a Redundant Power Supply1. Disconnect the power cord from the power supply.2. Using your thumb and index finger, squeeze the catch in the middle of the power supply handle (see Figure 6-2).3. Rotate the handle downward to release the power supply.4. Slide the power supply out of the chassis.Installing a Redundant Power Supply1. Slide the power supply into the chassis.2. When the power supply is fully inserted, rotate the power supply handle upward to lock the power supply in place.The power supply will not function until the handle is fully closed.3. Plug the power cable into the power supply, making sure that the cable passes through the power cable strain relief loop.Figure 6-2. Removing and Installing an Optional Redundant Power SupplyCAUTION: Before you perform this procedure, see "Safety First—For You and Your System" in "Troubleshooting Your System."CAUTION: See "Protecting Against Electrostatic Discharge" in the safety instructions in your System Information Guide.CAUTION: To prevent risk of personal injury from electrical shock, do not reach into an empty power supply bay.NOTICE: The power supplies are hot-pluggable. The system requires one power supply to be installed for the system to operate normally. The systemis in the redundant mode when two power supplies are installed. Remove and replace only one power supply at a time in a system that is powered on.NOTE: After installing a new power supply, allow several seconds for the system to recognize the power supply and determine whether it is workingproperly. The power-on indicator turns green to signify that the power supply is functioning properly (see Figure 2-3).