Rear assemblies 1 2 7 2 2 8 2 9 2 3 2 4 2 2 10 5 2 11 2 6 2 12 2 13 2 Figure 121. Rear of printer with cover removed 1 Developer/imaging drum bias supply (shown in two parts, the upper part is eliminated in all HP Color LaserJet 8550 printer models) 5 Post charger high-voltage (HV) module 6 Controller board 7 Sheet metal cover plate 8 Fan 2 2 Main relay PCA—located behind high-voltage power supply (callout 3) 9 Carousel motor (M1) 10 Fan 1 3 High-voltage power supply 11 Cleaning roller HV module 4 Cartridge motor (M3) 12 Formatter pan 13 Power supply 270 Chapter 6 - Removal and replacement EN