Dell OptiPlex 990 (Early 2011) - Manual (Page 40)

Installing The Power-Switch Cable
1. Slide the power-switch cable in through the front of the computer.
2. Secure the power-switch cable to the chassis.
3. Connect the power-switch cable to the system board.
4. Install the front bezel .
5. Install the cover .
6. Follow the procedures in After Working Inside Your Computer .
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