HP LaserJet M9040/M9050 Service Manual - Page 404

Table 7-13 Image defects (continued) Problem Cause Solution NOTE: When the ground is interrupted, the drum cannot discharge. This causes the drum to repel the toner leaving the bubble print pattern. Gray background Horizontal black lines See the Repeating defect ruler. Horizontal smudges The media fails to meet product specifications or is stored improperly. Print a few more pages to see if the problem persists. Turn the stack over in the tray, or rotate the stack 180° Use media that meets product specifications. The operating environment fails to meet Place the product in an environment that product specifications. meets product specifications. The toner density setting is incorrect. Adjust the toner density setting in the control panel Print Quality menu (turn off Economode). The print cartridge is faulty. Replace the print cartridge. The print cartridge is defective. Replace the print cartridge. The laser/scanner assembly is defective. Reseat the connectors on the laser/ scanner and the DC controller. Replace the laser/scanner if necessary. The DC controller is defective. Reseat the connectors on the DC controller and the laser/scanner assembly. Replace the DC controller if necessary. The paper path is contaminated or damaged. Replace the print cartridge if necessary. Check the fuser, and replace it if necessary. See the Repeating defect ruler. Horizontal white lines The paper path is contaminated or damaged. Replace the print cartridge if necessary. Check the fuser, and replace it if necessary. Replace the laser/scanner assembly and the DC controller if necessary. 386 Chapter 7 Solve problems ENWW