HP 8550 Service Manual - Page 493

The face or back of the copy paper is soiled (when made in double-sided copying mode) Unit Printer Cause Step Duplexing 1 unit 2 3 Checks Is the duplexing feeding roller 1 soiled? Is the feeding guide soiled? Is the reversing roller or the duplexing feeding roller 2 soiled? Yes/No Action YES Clean the roller. YES YES NO Clean the guide. Clean the roller. Replace the duplexing unit. The problem is not noted on a test print and is obviously a problem with the copy module. Unit Copy module Cause Step 1 2 3 4 Missing 5 service mode numbers Scanning 6 lamp CCD/CCD 7 unit 8 Checks Yes/No Action Is there a foreign object anywhere on or under the copyboard glass? YES Remove the foreign object. Execute auto gradation YES correction in user mode. Is the problem corrected? End. Does the mount for mirror 1/2/ NO 3 move smoothly on the rail? Remove the impediment to smooth movement. Clean the standard white plate, YES mirror 1/2/3, reflecting plate, and copyboard glass; then, execute FUNCTION > CCD > CCD-ADJ. Is the problem corrected? End. Compare the values listed on NO the service label of the copy module and to values listed under ADJUST in service mode. Are they identical? Enter the values listed on the service label. Remove the scanning lamp, YES and clean it. Then, remount the lamp, and execute FUNCTION > MISC-R > USELAMP. Is the problem corrected? End. Remove the CCD cover, and clean the surface of the CCD with a blower brush. Is the problem corrected? YES End. Are the contacts of the CCD/ CCD driver corrections correct? YES End. EN Copy module troubleshooting 491