Installing The Power Supply Unit (Psu) - Dell Precision Tower 3420 Owner's Manual

4. To remove the PSU:
a. Remove the screws at the back of the computer that secure the PSU to the computer [1].
b. Press the blue release tab [2] and lift the PSU away from the computer [3].

Installing the power supply unit (PSU)

1. Slide the PSU toward the back of the computer until it clicks into place.
2. Tighten the screws to secure the PSU to the computer.
3. Route the PSU cables through the retention clips.
4. Connect the PSU cables to their connectors on the system board.
5. Install the:
a. heat sink fan cover
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