Back to Contents PageSystem BoardDell™ OptiPlex™ GX400 Service ManualRemoving the System BoardReplacing the System BoardRemoving the System Board1. Turn off the computer and devices, disconnect them from their electrical outlets, wait at least 5 seconds, and then remove the computer cover.2. Lay the computer down on its right side.3. Rotate the power supply away from the system board.4. Remove the AGP card brace or AGP card clip.5. Remove all expansion cards.6. Remove all memory modules.7. Remove the microprocessor airflow shroud.8. Remove the microprocessor.9. Remove the microprocessor cooling fan.10. Disconnect all cables from the system board.11. Slide all drive brackets partially out of the chassis.12. Remove the screw that secures the system board to the bottom of the chassis.13. Slide the system board toward the front of the chassis until it stops.This unlocks the system board.14. Lift the front of the system board.15. Lift the system board out of the chassis at an angle.Removing the System BoardCAUTION: Before you perform this procedure, see "Precautionary Measures."NOTICE: Before disconnecting a device from the computer or removing a component from the system board, verify that the standby power light on the systemboard has turned off. To locate this light, see "System Board Components."