Dell OptiPlex 9020 All In One (Mid 2013) - Manual (Page 26)

Removing the I/O Board Shield
1. Follow the procedures in Before Working Inside Your Computer .
2. Remove the:
a) VESA stand
b) back cover
c) VESA mount bracket
d) power supply fan
e) system-board shield
3. Lift the I/O panel away from the computer.
4. Remove the screws that secure the power connector to the I/O board shield.
5. Remove the screws that secure the I/O board shield to the chassis. Loosen the power connector and press it down
the socket.
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