Lexmark T642 Service Manual - Page 157

4061-xx0 FRU 4 HVPS cable (part of front harness cable) System board Print quality-blank page Action Check the continuity of the HVPS cable. If incorrect, replace the cable assembly. If correct, replace the system board. FRU 1 Print cartridge 2 High voltage contact 3 HVPS 4 Front cable harness HVPS section 5 Printhead assembly Action Check the print cartridge for damage, especially the PC drum contact on the cartridge. Check the PC drum contact on the right side frame for damage, PC drum contact wear or contamination. If the contact is bent or damaged, replace the contact. Note: Inspect the HVPS PC drum contact on the board for damage or contamination. Check the fuse on the HVPS. If open, replace the HVPS. Check the voltages at J22 on the system board. Measure the following voltages from connector J22 to printer ground: • Printer Idle J15-5 measures +24 V dc • Printer Printing J15-5 measures +24 V dc If the voltages at J10-5 are incorrect, replace the system board. Check the front cable harness at J15 on the system board and at CN1 on the HVPS to make sure the harness is connected properly. If connected properly, check the continuity of the cable harness. If there is no continuity, replace the front cable harness. Generally a 93x service error is posted if the printhead assembly fails and the printer does not give a blank copy symptom. The printhead used in the printer does not have a mechanical shutter as previous laser printers. The printer is interlocked through the front top cover interlock switch. Print quality-random marks Service tip: The primary cause of random marks is due to loose material moving around inside the printer and attaching to the photoconductor, charge roll, or transfer roll. Symptom 1 Random marks Action Check the print cartridge for loose or foreign material that might be on the photoconductor. Check the transfer roll and charge roll for any pieces of material that are stuck to the rolls. Diagnostic information 2-117