HP 8000dn Service Manual - Page 421

Table 7-9. Black Pages (continued) Possible Cause Recommended Action 4. High voltage power supply circuit is defective (not supplying the correct negative voltage). Replace the High Voltage Power Supply PCA. See "Power Supply, High Voltage (HVPS)" on page 205 for instructions. 5. DC Controller PCA is defective. If the DC Controller turns on the laser beam continuously, the entire surface of the Photosensitive drum is neutralized causing a completely black page. Replace the DC Controller PCA. See "PCA, DC Controller" on page 197 for instructions. 6. Laser/Scanner Assembly is faulty (turning laser on continuously). Replace the Laser/Scanner Assembly. See "Laser/Scanner Assembly" on page 189 for instructions. 7. Connectors between the Laser/Scanner Inspect and reseat the connectors. unit and DC Controller are not seated Replace cables as necessary. properly or are defective. Table 7-10. Fading Print Possible Cause Recommended Action 1. Toner supply is low. Shake the cartridge gently to redistribute the toner, or replace the cartridge. 2. Print Density is set incorrectly. Change to a darker setting and retry printing. 3. EconoMode is on. EconoMode saves toner by reducing the dot density. This may appear to be a print quality problem in some cases. Turn EconoMode off. Verify that EconoMode is not being enabled by either the printer driver or the job application. 4. Paper does not meet specifications. The moisture content, conductivity, or surface finish may not work correctly with the electrophotographic process. Try a different paper lot (see HP LaserJet Printer Family Paper Specifications Guide). EN Image Quality 397