Phaser 4400 Laser Printer Service Manual 3-1TroubleshootingIntroductionThis section covers two types of troubleshooting procedures: Troubleshooting procedures for problems not directly associated with errormessages or codes Troubleshooting Procedures for Image-quality (IQ) problemsTroubleshooting procedures will normally isolate a problem to a specific componentor subassembly, in some cases including the wire harnesses.In the Yes/No steps of the procedures, a Yes/No response will either lead you to thenext step or will indicate a corrective action. When you complete the indicatedcorrective action, restart the System Check to verify that the problem has beencorrected.MeasurementsPower and signal grounds are connected to frame ground. You can perform all circuittroubleshooting using the metal frame (chassis) as the grounding point. If you needmore information to locate connectors or test points, refer to Wiring Data on page 9-1.Unless otherwise specified, the following voltage tolerances are used within thissection:Section ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2Index of Troubleshooting Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Image-Quality Checkout Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-41Index of Image-Quality Checkout Procedures . . . . . . . . . . . . . . . . . . . . . . . . 3-41Image-Quality Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . . . . . .3-53Index of Image-Quality Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . 3-53Voltage MeasurementsStated Measured Stated Measured+3.3 VDC +3.0 to 3.6 VDC +24.0 VDC +21.6 to +26.4 VDC+5.0 VDC +4.8 to +5.2 VDC 0.0 VDC Less than +0.5 VDC
