HP 4550 Service Manual - Page 178

Note CAUTION Drum drive assembly To remove the drum drive assembly Turn the printer off, wait five seconds, and then unplug the printer. 1 Open both front drawers. Make sure the imaging drum is protected from light. Exposure to light for more than 15 seconds can seriously damage the imaging drum. 2 Remove the formatter pan assembly. 3 Remove the power supply. 4 Disconnect the two cables from the HVPS and free them from the cable stay. 5 Remove the screw that secures the cable trough to the drum drive assembly as shown in Figure 6-34. Figure 6-34 Drum drive assembly removal and replacement (1 of 3) 6 Carefully release the cable trough by pulling out slightly on the bottom and releasing the clip. Depress the plastic v-shaped clip underneath the DC controller to loosen the cable guide. Slide the trough toward the rear of the printer until it is free. 7 Disconnect J204 on the developing PCB and free it from its cable stay. 8 Remove the eight black screws from the drum drive assembly shown in Figures 6-35 and 6-36. 9 Gently slide the drum drive assembly straight out from the printer assembly taking care not to damage the cable. 176 Removal and replacement C7085-90921