Dell Precision 7820 Owner's Manual page 28

3 To remove the front input and output(I/O) panel:
a Disconnect the intruder switch cable [1], USB 3.1 cable [2], front I/O power cable [3], USB 3.1 cable [4], Speaker cable [5], Audio
cable [6]
NOTE:
end. Pulling the cable wires may loosen them from the connector.
b Remove the screw that secures the front I/O panel to the chassis.
28 Removing and installing components
Do not pull the connector by the cable wires. Instead, disconnect the cable by pulling the connector