Dell 2135cn Color Laser Printer - Manual (Page 205)

Installing the PHD Unit
1. Press the side button and open the front cover.
2. Turn the four PHD lock levers counterclockwise to unlock the unit.
3. Hold the gray tabs, and then pull the PHD unit out of the printer totally.
4. Completely remove the four yellow ribbons from the PHD unit.
NOTICE: Do not touch the belt unit.
NOTICE: Do not remove the protective sheet while removing the PHD unit.