HP 8550 Service Manual - Page 491

The copy has a smudged or uneven image Unit Printer Cause Separation sensor Fusing assembly Step 1 2 High- 3 voltage PCB 2 4 Fusing 5 assembly Registra- 6 tion roller, feeding roller 2 Separ- 7 ation static- eliminator Separ- 8 ation staticeliminating bias PCB dc 9 controller PCB Checks Does the lever of the separation sensor move poorly? Yes/No Action YES Replace the sensor lever. Is the fusing assembly inlet guide soiled? Are the contacts soiled on either of the following? l upper fusing roller YES l fusing/separation bias Are connectors J5005 and J5006 NO on the high-voltage PCB 2 connected securely? Replace the high-voltage PCB 2. Is YES the problem corrected? Is the upper fusing cover securely NO fitted to the fusing assembly? Is the drive gear of the registration YES roller or the feeding roller itself worn? Clean the contact. If it is defective or damaged, replace it. Also, check for a displaced contact to place it correctly. Connect them securely. End Fit the cover securely. Replace the worn part. Is the charging wire of the separation static eliminator broken? YES Replace the separation static eliminator. Are connectors J5600, J5601, and NO J5602 on the separation staticelimination bias PCB connected securely? Connect them securely. Replace the separation static eliminator PCB. Is the problem corrected? YES NO End. Replace the dc controller PCB. EN Copy module troubleshooting 489