Gray Background (continued) Horizontal Black Lines Horizontal Dots C4170-90959 Image Formation Troubleshooting 121 Possible Cause Action Poor contact between the primary bias contact on the Engine Controller Assembly and toner cartridge contact. Check developer bias spring. Possible Cause Action Toner Cartridge not seated properly. Remove the Cartridge and reinsert it. Repetitive defect. If the lines are repeated at a consistent interval down the page, this is a repetitive defect.
Refer to “Repetitive Defect Ruler” (page 127) to isolate and fix the problem Fuser entrance guide is dirty Clean the guide Fuser Film Unit is scarred Replace the Fuser FIlm Unit after determining and removing the cause of the scarring Toner Cartridge is scarred. Replace the Cartridge. Possible Cause Action Deformed or deteriorated Transfer Roller. Replace the Transfer Roller. Dirty static eliminator teeth. Clean the static eliminator. Poor contact between the Static Eliminator and the Engine Controller Assembly. Inspect the contacts. If parts are damaged or deformed, replace them.
Poor contact between the transfer roller contact on the Engine Controller Assembly and the transfer charging roller shaft contact Inspect the contacts. If parts are damaged or deformed, replace them. Defective Engine Controller Assembly. Replace the Engine Controller Assembly and the Intermediate PCB.