5-34 Phaser 8400/8500/8550/8560 Color Printer Service ManualPrint-Quality TroubleshootingAnalyzing Service Test PrintsThis section shows how to select and analyze all test prints stored in theprinter. A variety of test prints are available in the Hidden Service Menu to aidin determining the quality of output from the printer and to assist introubleshooting problems. To enter the Hidden Service Menu: from theService Tools menu, press and hold the Up Arrow and Down Arrow buttons.NoteDefects revealed by the prints may not occur in the course of ordinaryprinting. In servicing the printer, you should minimize the defects shownby the prints but not necessarily eliminate them.Weak/Missing JetThis print shows which jets are not outputting enough, if any, ink compared toits neighboring jets. Note that the yellow jets’ bands have a small amount ofcyan ink added to them, which tints them green, to make them more visible.Look for: No interlacing is used in this print; expect light/dark variation betweenjets. Look for much lighter colored vertical bands in the horizontal bars. Weakjets in the yellow band are distinguished by a cyan tint.Causes: A jet may be partially clogged; perform Printhead clean/purge cycleson the Printhead to remove contaminants from the poorly-performing jet. If jetsubstitution mode is required, see “Jet Substitution Mode” on page 6-9. Testthe purge system and the wiper blade performance. Turn the printer off for 4 to6 hours (or overnight, if practical). Then perform a clean/purge cycle again.There may be a problem in the Purge Pump or the Wiper Assembly. Verifythat Xerox ink is being used. Follow the instructions on the “PrintheadTroubleshooting Checklist”.NoteInclude two prints of this test print with any returned Printhead.74 75 76 77 78 79 80Weak jets8500-048
