Dell OptiPlex 390 (Mid 2011) - Manual (Page 53)

Installing the System Board
1. Align the system board to the port connectors on the back of the chassis
and place the system board in the chassis.
2. Tighten the screws securing the system board to the chassis.
3. Close the expansion-card latch.
4. Connect the cables to the system board.
5. Install the
heat sink .
6. Install the expansion card .
7. Install the hard drive .
8. Install the front bezel .
9. Install the cover .
10. Follow the procedures in After Working Inside Your Computer .
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