HP 8000dn Service Manual - Page 434

Note Drum Rotation Functional Check The photosensitive drum, located in the toner cartridge, must rotate for the print process to work. The photosensitive drum receives its drive from the Main Drive assembly. To verify whether the drum is rotating: 1 Open the top cover. 2 Remove the toner cartridge. 3 Mark the cartridge's drive gear with a felt-tipped marker. Note the position of the mark. 4 Install the toner cartridge, and close the top cover. The start-up sequence should rotate the drum enough to move the mark. 5 Open the printer, and inspect the gear that was marked in step 3. Verify that the mark moved. If the mark did not move, inspect the Main Drive assembly to make sure that it is meshing with the toner cartridge gears. If the drive gears appear functional, and the drum does not move, replace the toner cartridge. This test is especially important if refilled toner cartridges have been used. High-Voltage Power Supply Check The High-Voltage Power Supply PCA provides the necessary voltages for the electrophotographic processes (see figure 7-11 on page 411). A method for verifying the high-voltage system is given below: Toner cartridge connection points Visually inspect the four connection points on the inside right end of the toner cartridge. If they are dirty or corroded, clean the connections. Clean using only alcohol. If damaged, replace the toner cartridge. High voltage contacts The high voltage contact springs mount on the High Voltage Power Supply PCA and protrude through the toner cartridge cavity to contact the toner cartridge. Verify that the contacts are not dirty or corroded and that the spring action is functional. If dirty, clean using only alcohol. If damaged, replace the High Voltage Power Supply PCA (see "Power Supply, High Voltage (HVPS)" on page 205 for instructions). 410 Chapter 7 Troubleshooting EN