Dell 9478N Owner's Manual page 52

6. Remove the disk-drive cage.
About this task
The following image indicates the location of the optical-drive assembly and provides a visual representation of the removal
procedure.
Steps
1. Remove the single (M2x2) screw to release the optical drive from the disk-drive cage.
2. Slide the optical drive out of the disk-drive cage.
52 Rimozione e installazione delle unità sostituibili dal cliente (CRU)