Supermicro SuperServer E403-9D-4C-FRDN13+ User Manual page 23

Enabling the Top Cover Lock Function
The chassis includes a lock plate that allows the top cover to be locked.
1. Pull the lock plate into a vertical position.
2. Close the fan cover. Make sure the lock plate fits through the slot on the cover.
3. Install two screws on the fan cover.
4. Install a lock on the lock plate.
Chapter 2: Maintenance and Component Installation
Figure 2-4. Pull the Lock Plate Up
23