Lexmark T620 Service Manual - Page 146

4069-5XX/7XX FRU 2 Charge Roll Assembly Charge Roll Link Arm 3 HVPS Action Check the charge roll for any signs of toner buildup or other contamination on the outer edges that correspond to the bands on the page. Check the charge links and arms for proper operation, binds or incorrectly mounted counterbalance springs. Repair or replace as necessary. Check the following voltages at J25-8 on the system board: Printer Idle J25-8 measures 0 V dc Printer Printing Test Page J25-8 voltage changes from 0 V dc to +4 V dc If the voltage does not vary, check the continuity of line J25-8 in the front cable harness. If there is no continuity, replace the cable harness. If there is continuity, replace the HVPS. If this does not correct the problem, replace the system board. Turn the printer off and check the resistance between J25-7 and printer ground. The resistance measures approximately 0 ohms. If incorrect, make sure the system board is mounted correctly and securely grounded. If correct, replace the system board. 2-118 Service Manual