HP 4700n Service Manual - Page 470

Table 7-25 Causes for horizontal lines Cause Solution The photosensitive drum has scars that run from end to end. Replace the print cartridge for the affected color. The fuser sleeve has scars that run from end to end. Replace the fuser. White horizontal lines This table contains information about the causes of and solutions for white horizontal lines. Table 7-26 Causes for white horizontal lines Cause Solution The photosensitive drum has scars that run from end to end. Replace the print cartridge for the affected color. The ETB belt has horizontal scars. Replace the ETB. Calibrate the printer after replacing the ETB. See Full Calibrate Now on page 539. Missing color This table contains information about the causes of and solutions for missing color. Table 7-27 Causes for a missing color Cause The primary charging roller is defective. A poor contact exists in the developing bias contacts of the high-voltage PCB and the print cartridge. The laser/scanner unit is defective. The high-voltage PCB is defective or one of the connections is loose. The DC controller may require a firmware upgrade or the connector to the high-voltage PCB (J1006) is disconnected or not seated properly. Solution Replace the print cartridge for the missing color. Clean the contacts. If they are still dirty after cleaning, or if they are damaged, replace the print cartridge or the highvoltage contacts. Replace the high-voltage PCB. See Highvoltage power supply PCB on page 324. Replace the laser/scanner for the missing color. See Laser/ scanner assembly on page 287. Calibrate the printer after replacing the laser/scanner. See Full Calibrate Now on page 539. 1. Check the connections. 2. Replace the high-voltage PCB. See High-voltage power supply PCB on page 324. 1. Upgrade formatter and DC Controller firmware, which can be found in a single .rfu file from http://www.hp.com/ support/clj4700 or http://www.hp.com/support/cp4005. 2. Check the connector (J1006) on the DC controller PCB to make sure it is seated correctly. 450 Chapter 7 Troubleshooting ENWW