HP 8550 Service Manual - Page 490

The print has an inadequately fused toner image Unit Printer Cause Step Fusing 1 assembly dc 2 controller PCB Checks Is the upper or lower fusing roller scratched or defective? Is the upper or lower fusing thermistor soiled? Yes/No Action YES Replace the upper or lower fusing roller or the fusing assembly. YES Clean the upper or lower fusing thermistor. NO Replace the dc controller PCB. The copy has a distorted or color-displaced image Unit Printer Cause Drum motor drive assembly Step 1 Laser/ 2 scanner assembly 3 dc 4 controller PCB Checks Yes/No Action Is the drive gear between the drum YES cartridge and the drum motor, or between the intermediate transfer drum and the drum motor, worn or cracked? Replace the worn or cracking gear. Are connectors J1001, J2, and NO J901 of the laser/scanner assembly connected securely? Connect them securely. Replace the laser/scanner assembly. Is the problem corrected? YES End Are connectors J205 and J211 on NO the dc controller PCB connected YES securely? Connect them securely. Replace the dc controller PCB. 488 Chapter 7 - Troubleshooting EN