HP DesignJet 500 / 500PS / 800 / 800PS Series Service Manual (P/N C7769-60154)

• Exact model coverage: HP DesignJet 500 24-inch C7769B and 42-inch C7770B; 500PS C7769C/C7770C; 800 C7779B/C7780B; and 800PS C7779C/C7780C.
• Fault isolation: System-error descriptions and corrective-action logic, the Error Log, Power Switch LED, boot-up sequence, formatter/accessory-card LEDs, Printhead History, and the Diagnostic Print A/B troubleshooting flowchart.
• Built-in service functions: Ink Supply Station, Carriage Movement, Paper Advance, and print-quality tests; EEROM setup and usage-counter reset; drive-roller, carriage-unlock, tube-priming, cutter, and ink-tube utilities; plus printhead/PPS, color, and media-advance calibrations.
• Major repair procedures: Illustrated removal and installation for the electronics module, power supply, formatter, LAN card, motors, service station/aerosol fan, ink-supply tubes, carriage/belt/trailing cable, encoder strip, drive roller, gear assemblies, vacuum fan, cutter, platen, and pinch-arm hardware.
• Parts identification: Exploded diagrams and HP part numbers distinguish 24- and 42-inch tubes, trailing cables, belts, encoder strips, interconnect cables, pinch-arm mechanisms, cutter guides, drive rollers, roll-feed parts, and printer supports.
• Document identity: First Edition, August 2000; a 286-page Hewlett-Packard service manual in a 289-page PDF. The file also contains two non-HP front pages and one blank trailing page. This is a service publication, not an operator’s guide.

Built-In Diagnostics, Error Logging, and Calibration

This manual follows the HP diagnostic path rather than jumping directly from a symptom to a replacement. The system-error chapter explains how each four-digit code identifies the affected subsystem and the required response. Its coverage reaches the Main PCA/electronics module, carriage, formatter, network card, trailing and interconnect cabling, ink-supply and service-station systems, paper and scan axes, fans, sensors, firmware, memory, media advance, carriage movement, printhead firing, and ink pumping.

The Error Log retains the last ten system failures with the code, firmware line, and date. Printhead History stores the last five records for each selected color, including recovery level, ink use, paper-crash history, removal status, and reported errors. Together, those records help determine whether the printer is repeatedly damaging printheads or whether printheads were replaced before the built-in recovery routine was completed.

The service-test chapter is particularly useful before a repair. The Ink Supply Station test checks empty-cartridge sensing. Carriage Movement evaluates scan-axis friction, service-station blockage, and encoder response. Paper Advance separates paper-axis motor, roller-encoder, drive-roller, and transmission-gear faults. HP repeatedly directs the technician to run the applicable test before replacing an assembly.

Calibration coverage includes standard and special printhead alignment, PPS calibration for vertical-line straightness, media-specific color calibration, Advance Calibration, and Factory Advance Calibration. The factory procedure is tied to defined repair conditions, including drive-roller or paper-axis motor work and combined replacement of the electronics module and Ink Supply Station.

EEROM coverage goes beyond basic identification. It documents model and serial configuration, the backup EEROM in the Ink Supply Station, reset-to-default requirements, and usage-counter reset for the scan axis, paper axis, service station, spittoon, pinch lift, cutter, carriage, and ink system. Counter resets are tied to actual component replacement so the stored maintenance history remains meaningful.

Component Repair, Parts Identification, and System Architecture

The removal chapter is arranged in teardown order and uses repair photos, tool illustrations, and a screw-type table with the corresponding HP part numbers. Electronics work covers the formatter, LAN card, electronics module, power supply, Interconnect PCA, and internal cabling. Mechanical repair reaches the scan-axis motor, carriage and belt, encoder strip, paper-axis motor, drive roller and gears, Ink Supply Station and tubes, service station/aerosol fan, vacuum fan, cutter system, print platen, pinch-arm components, and roll-feed hardware.

Chapter 7 pairs component tables with exploded views and HP service-part numbers. Representative visuals include Figure 7: Electronics Module, Figure 10: Ink Delivery System, Figure 11: Service Station and Spittoon, Figure 15: Drive Roller Encoder Sensor, Figure 17: Carriage Assembly, and Figure 21: Drive Roller. The tables assign different part numbers to many 24- and 42-inch components, helping prevent the wrong tubes, cables, belts, encoder strips, guides, or drive components from being ordered.

The SKU overview separates the 16 MB DesignJet 500 and 500PS configurations from the DesignJet 800 and 800PS models. The 800 uses 96 MB memory expandable to 160 MB, while the 800PS is listed with 160 MB; both have standard formatter and network hardware and a 6 GB hard drive. The functional overview explains the Main PCA, Kayak and Navata control logic, backup EEROM, Interconnect PCA distribution, power-supply outputs, off-axis ink delivery, tube operation, printhead capping and wiping, and aerosol-fan integration.

Two manual-specific cautions are worth noting. Hot-inserting an EIO card or formatter can burn the Main PCA, and a failed Ink Supply Station sensor or spring can make the printer pump from an empty cartridge stall and dry-fire the printheads. Disconnect the printer from power before internal repair and follow the stated ESD procedures when handling printed circuit assemblies. HP identifies these procedures as work for qualified service personnel and directs normal operating information to the separate User and Quick Reference Guides.