HP Designjet 4500/4520 Printer Series Service Manual

• 5th Edition (March 2009) service manual covering the HP Designjet 4500 and 4520 printer family, including PS and MFP variants, in a 663-page PDF.
• Scan-axis repair includes carriage assembly and belt replacement, encoder strip and sensor service, and removal of trailing cables, carriage flex cables, and the scan-axis motor.
• Roll 1 and Roll 2 sections combine Media Drive and Back Tension Arm tests with feed-roller, feed-motor, drawer-sensor, and spindle-support replacement.
• Ink-system procedures cover Ink Supply Station (ISS) and Air Pressurization System (APS) replacement, ink-tube priming, Air Pump System testing, and Bag Broken Recovery.
• Factory calibrations address the line sensor, drop detector, service station, vacuum fans, and paper advance, with Carriage Setup for resetting ink-short thresholds after PCA replacement.
• Separate stacker repair coverage includes error-code diagnosis, operational testing, and replacement of the heating lamp, heat roller, transport belt, drive motor, and temperature sensors.

Covered models are the 4500 (Q1271A), 4500ps (Q1272A), 4500 MFP (Q1276A), 4520 (CM767A), 4520ps (CM768A), and 4520 MFP (CM769A). MFP coverage is printer-side only; scanner repair is outside this manual.

Troubleshooting and System Diagnostics

The 30-step boot-up sequence, buzzer troubleshooting tables, and PCA LED indicators support fault isolation in the electronics module. Main PCA faults are covered through buzzer analysis and the Electronics Module Test; the board-level LED maps identify the Interconnect and PrintMech PCAs.

System error codes cover hardware failures such as scan-axis motor overloads and firmware communication errors. Service information pages explain event logs, ink-supply history, calibration status, and belt and motor cycle counts, including access through the Embedded Web Server when the printer cannot print.

The Electronics Module Test excludes the EIO card and hard disk. The separate Carriage Assembly, Ink Delivery System, SVS/Aerosol Fan, and Vacuum Fans test entries are marked not implemented in this edition.

Hardware Revisions and Repair Details

The APS section separates 4500 printers before serial SG6ABH9014 from SG6ABH9014 onward, with different tubing and mounting arrangements. Trailing-cable instructions distinguish original and replacement Gamut PCA connectors, adapter requirements, and old/new Top Crane Covers. The Feed Roller Material Change utility configures the printer for replacement roller material.

Error 71:19 Recovery covers printer-identity restoration after the hard disk and ink supply tubes have both been replaced.

Drive-roller installation includes datum checks to eliminate axial play. Repair cautions identify two easily damaged areas: withdrawing the Roll 1 Module incorrectly can damage its Back Tension Arm, and refitting the right cover with the cleaner door closed can damage the Printhead Cleaner Door Sensor.

Parts, Diagrams, and Service Tools

Electronics repair procedures cover formatter and power-supply replacement, with cable routing and connector identification. Parts tables distinguish 4500 and 4520 formatter, memory, and hard-drive assemblies and identify voltage-specific stacker heating lamps and fuses.

Exploded Electronics Module and Carriage Assembly drawings link component locations to HP part numbers; the Roll 2 Module and stacker Rollers and Transport Belt views cover the media-handling assemblies.

The tool listings identify printer service tool kit Q1271-60728, including right-angle keys for Roll 1 guide access.

Specification and Reference Data

Technical specifications cover ink-cartridge capacities, electrical diagnostic limits, and calibration acceptance criteria. Printhead health thresholds are tied to nozzle-outage counts from the last drop-detection check, while the supplies reference explains cartridge, printhead, and cleaner status messages.

The Nozzle Print Test checks individual nozzles without error hiding. Advanced Banding Troubleshooting for Experts provides flowcharts for separating printhead defects from media-advance issues. Dedicated sections address Dark Light Zone Banding and black-printhead decap.

Preventive maintenance covers drive-roller and platen cleaning and carriage lubrication. It explains how carriage cycles trigger Maintenance #1 and accumulated spittoon ink triggers Maintenance #2, both covered by Preventive Maintenance Kit Q1273-60061. The Reset Life Counters utility handles kit-level and individual replacement-part counters.

Working with high-voltage printer electronics carries inherent risks; always disconnect the printer from its power source and follow standard electrostatic discharge (ESD) safety protocols before accessing internal boards. HP specifies these procedures for qualified service personnel. Diagnostic test mode disables cover sensors, so opening the window does not stop a moving carriage.