Dell OptiPlex 990 (Early 2011) - Manual (Page 39)

System Board
15
Removing the System Board
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 power supply .
6. Remove the heat sink .
7. Remove the memory .
8. Remove the input/output panel .
9. Remove the wireless module .
10. Remove the speaker .
11. Disconnect all the cables connected to the system board, and move the
cables away from the chassis.
12. Unthread and move the internal antenna from the chassis.
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