Xerox 4400DT - Phaser B/W Laser Printer, Service Manual, Page: 99 / 503

3-2 Phaser 4400 Laser Printer Service Manual
Troubleshooting Procedures
Verifying AC Power
There is a possible problem with AC power.
Warning: Improper connection of the grounding conductor can
result in the risk of electrical shock.
The following must be observed:
■
Never use a ground adapter plug to connect the machine to a power source.
■
Never attempt any maintenance function that is not specifically called out in
the service procedures.
■
Never remove any covers that are fastened with screws, unless so instructed
in the service procedures.
Caution: If any of the voltage measurements are not as specified in
the following steps, the cause must be corrected. Caution
the customer NOT to connect the machine to the wall
outlet. Advise the customer that a licensed electrician must
correct the wiring. Do not attempt to correct the wiring
yourself. If you later find the condition has not been
corrected, inform your manager in writing of the improper
wiring.
Index of Troubleshooting Procedures
Verifying AC Power . . . . . . . . . . . . . . . . .3-2 Print Cartridge Sensor Assembly . . . . . 3-24
DC Power (LVPS). . . . . . . . . . . . . . . . . . .3-4 Tray Motor Assembly Checkout . . . . . . 3-26
DC Power Loading . . . . . . . . . . . . . . . . . .3-6 Registration Clutch . . . . . . . . . . . . . . . . 3-27
Toner Sensor Failure . . . . . . . . . . . . . . . .3-8 Turn Roller Clutch Assembly . . . . . . . . . 3-28
Inoperative Printer . . . . . . . . . . . . . . . . . .3-9 Tray 1 Feed Clutch . . . . . . . . . . . . . . . . 3-29
Malfunctioning Front Panel. . . . . . . . . . .3-11 MPT Pick Up Solenoid . . . . . . . . . . . . . 3-30
Inoperative Front Panel . . . . . . . . . . . . .3-13 Image Processor Isolation. . . . . . . . . . . 3-31
Erratic Printer Operation. . . . . . . . . . . . .3-13 High-Voltage Power Supply (HVPS)
Assembly. . . . . . . . . . . . . . . . . . . . . . . . 3-31
Power Supply . . . . . . . . . . . . . . . . . . . . .3-14 Electrical Noise . . . . . . . . . . . . . . . . . . . 3-33
Main Motor Assembly. . . . . . . . . . . . . . .3-15 Exit Sensor . . . . . . . . . . . . . . . . . . . . . . 3-34
Laser Assembly . . . . . . . . . . . . . . . . . . .3-17 Exit Motor . . . . . . . . . . . . . . . . . . . . . . . 3-35
Fuser Assembly . . . . . . . . . . . . . . . . . . .3-18 550-Sheet Feeder Feed Clutch . . . . . . . 3-36
Registration Sensor . . . . . . . . . . . . . . . .3-20 Stacker Full Sensor . . . . . . . . . . . . . . . . 3-37
MPT No Paper Sensor . . . . . . . . . . . . . .3-21 Stacker Offset Operation Not Performed3-38
Tray 1 No Paper Sensor. . . . . . . . . . . . .3-22 Envelope Feed Clutch . . . . . . . . . . . . . . 3-38
Output Tray Full Sensor . . . . . . . . . . . . .3-22 Envelope No Paper Sensor. . . . . . . . . . 3-39
Stack Height Sensor Checkout. . . . . . . .3-23