HP 4700n Service Manual - Page 467

All black or solid color This table contains information about the causes of and solutions for all black or solid color. Table 7-20 Causes for an all black or solid colored image Cause A poor contact exists in the drum ground, primary charging bias, and developing bias contacts of the high-voltage PCB and the print cartridge. The primary charging roller is defective. The high-voltage contacts are broken or damaged. The high-voltage PCB is defective. The laser/scanner unit is defective. The DC controller may require a firmware upgrade or the connector to the high-voltage PCB (J1006) is disconnected or not seated properly. Solution Clean the contacts on the cartridge for the affected color. If they are still dirty after cleaning, or if they are damaged, replace the affected cartridge. Replace the print cartridge for the affected color. Replace the high-voltage contacts for the affected color. Replace the high-voltage PCB. See High-voltage power supply PCB on page 324. 1. Run the component test to verify that the laser/scanner unit is defective. See Component test (special mode test) on page 532. 2. Replace the affected laser/scanner unit. See Laser/ scanner assembly on page 287. 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. Dots in vertical lines This table contains information about the causes of and solutions for dots in vertical lines. ENWW Image defects 447