2009 Xerox WorkCentre Pro 423/428 Printer Service Manual

This Xerox WorkCentre Pro 423/428 service manual, dated 03/03, covers digital copier, printer, and fax configurations, including duplex and finisher options.

• Service diagnostics: Service Call Procedures, Status Indicator RAPs, internal code lookup tables, and C/E self-diagnostics for machine, memory, and communication faults.

• Image quality and optics: Image Quality RAPs, lens/CCD and ROS replacement, carriage alignment, and registration and magnification adjustments.

• DADF and paper handling: Pickup, feed, and retard roller replacement, bypass tray service, and jam diagnosis through document, registration, and duplex paths.

• Fuser and output systems: Fuser assembly, pressure roll, and heater rod replacement, OCT service, and finisher motor, belt, and roller repairs.

• Control boards and software: MCU/SW, IIT/IPS, and ESS PWB replacement, machine memory functions, and firmware upgrade procedures.

• Wiring and parts: Block Schematic Diagrams, Plug/Jack Location Diagrams, illustrated spare parts lists, and accessory installation procedures.

This manual is suited to copier service technicians familiar with electrical testing and C/E diagnostics.

Status Codes and Circuit Tracing

The Service Call Procedures connect reported symptoms with the appropriate repair analysis procedure. Status Code Lists distinguish displayed faults from internal codes, with dedicated coverage for HDD failures, memory faults, feed-in and registration sensors, and inter-system communication.

ISDN and Super G3 fax sections extend communication diagnosis beyond a general error list. The X Status Codes Flow Chart RAP connects transmission symptoms with the relevant communication checks.

Cross-referencing a U-RAP with its BSD and Plug/Jack Location Diagrams helps identify the board, connector, and harness involved before selecting a replacement part. Power RAPs cover the +3.3VDC, +5VDC, and +24VDC circuits and distinguish LVPS, MCU/SW, and ESS checks.

Copy Quality, DADF Registration, and Optical Repairs

Image Quality RAPs address faint or blank copies, banding, skew, poor fusing, and other output defects. The manual identifies A3 Test Pattern 499T00247 and A4 Fax Test Pattern 499T00281 for copy and fax quality evaluation, alongside internal test patterns and Image Quality Specifications.

Optical service includes the exposure lamp, lens/CCD assembly, and carriage cables. REP 6.4 warns against removing both carriage cables together and references full-rate/half-rate carriage alignment after replacement.

DADF adjustments distinguish lead-edge registration, side registration, and document-feed magnification. The related repair sections cover feeder rollers, counterbalances, and document-size sensing.

Fuser, OCT, and Finisher Service

Fuser work extends beyond assembly replacement to separate pressure-roll and heater-rod procedures. The U4-2 Fuser Failure RAP also addresses the associated NVM fault-clearing requirement.

OCT and finisher sections cover output transport, stapler and compiler motors, drive belts, and roller assemblies. Finisher-specific RAPs distinguish transport jams from interface and interlock faults.

Board Replacement, Parts Variants, and Wiring References

MCU/SW PWB replacement includes NVM settings and counter restoration; ESS PWB replacement addresses the EPROM that stores MAC addresses. The board procedures warn that electrostatic discharge can damage electronic components.

The parts lists distinguish regional components and serial-specific DMO-E versions. Software upgrade instructions cover P-ESS, DC SYS, and MF systems, using the corresponding firmware files or replacement DIMMs.

Wiring examples include Main Power On, Document Set and Feeding, Carriage Scan, Fusing Heat Control, and ESS (Printer). Connector location drawings accompany the schematics. Accessory procedures cover options such as the duplex unit, stapler finisher, ISDN/G4, and Internet FAX kits.

Follow the manual's electrical isolation, laser, and hot-fuser precautions during internal service work.

A Preview of Electrical Test References

These are a few of the electrical test values included in the manual. For DC measurements referenced to the frame unless a note specifies otherwise, Wiring Data gives +4.5 to +5.3VDC for the +5VDC rail and +22.0 to +25.7VDC for the +24VDC rail.

The AC Power RAP also includes a 100VAC check at LVPS J8-3/J8-6 within its 100V-model test sequence.

Searchable Text, Bookmarks, and Diagram Detail

Text navigation and wiring labels: Service text and section headings are searchable, and embedded bookmarks reach all major sections and many individual procedures. Labels within schematic images are not text-searchable. Small wiring labels require zooming for comfortable reading.

One printable English 676-page PDF contains 20 introductory and safety pages plus 656 pages across the eight service sections. Blank and section-divider pages are already included in that total.