HP EliteDesk 800 G3 SFF Hardware Reference Manual page 28

Removing a 9.5 mm slim optical drive
1. Remove/disengage any security devices that prohibit opening the computer.
2. Remove all removable media, such as compact discs or USB flash drives, from the computer.
3. Turn off the computer properly through the operating system, and turn off any external devices.
4. Disconnect the power cord from the AC outlet and disconnect any external devices.
IMPORTANT:
as the system is plugged into an active AC outlet. To prevent damage to internal components, you must
disconnect the power cord from the power source before opening the computer.
5. If the computer is on a stand, remove the computer from the stand.
6. Remove the computer access panel.
7. Disconnect the power cable (1) and data cable (2) from the rear of the optical drive.
IMPORTANT:
damaging the cable.
22 Chapter 2 Hardware upgrades
Regardless of the power-on state, voltage is always present on the system board as long
When removing the cables, pull the tab or connector instead of the cable itself to avoid