Dell OptiPlex 790 (Early 2011) - Manual (Page 41)

Power Supply
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Removing the Power Supply
1. Follow the procedures in Before Working Inside Your Computer .
2. Remove the cover .
3. Remove the front bezel .
4. Remove the drive cage .
5. Remove the fan shelter .
6. Disconnect the 4-pin power cable from the system board.
7. Unthread the 4–pin power cable from the chassis clips.
8. Disconnect the 24-pin power cable from the system board.
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