HP 4700n Service Manual - Page 465

Light color This table contains information about the causes of and solutions for light color. Table 7-16 Causes for light color Cause Solution A poor contact exists in the transfer bias contacts between the ETB and the printer. Clean the contacts for the affected color. If the contacts are still dirty after cleaning or if they are damaged, replace the contacts or the ETB. Calibrate the printer after replacing the ETB. See Full Calibrate Now on page 539. The transfer charging roller is worn or damaged. The photosensitive drum is worn. The ETB alienation system is defective. Replace the ETB. Calibrate the printer after replacing the ETB. See Full Calibrate Now on page 539. Replace the print cartridge for the affected color. 1. Run the component test to verify that the ETB alienation system is defective. See Component test (special mode test) on page 532. 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. 2. Replace the ETB. 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. Dark image This table contains information about the causes of and solutions for dark images. Table 7-17 Causes for dark images Cause The image density is not adjusted correctly. The color misregistration detection unit is dirty. Solution Decrease the density for the affected color. Clean the lens on the color misregistration detection unit. ENWW Image defects 445