HP DL120 - Manual (Page 43)

Removal and replacement procedures 43
To replace the default optical disc drive:
1. Remove the primary and secondary access panels.
2. Remove the default optical disc drive from the chassis.
a. Disconnect the data and power cables from the ODD (1).
b. Remove the screw that secures the ODD carrier (2).
Reuse these screws when you install the new ODD.
c. Push the ODD carrier towards the front of the chassis, and then slide it out completely (3).
3. Remove the ODD backplane board.
a. Remove the two screws that secure the ODD backplane board (1).
b. Detach the backplane board from the ODD module (2).
Reuse this backplane board when you install the new ODD.