Lexmark C770, C772, C780 & C782 Printer Service Manual Set (P/N 12G9688)

The 5061 service manual provides the diagnostic checks, repair procedures, and parts references. The 5061 bulletins add fault-specific guidance for symptoms such as recurring jams and printhead errors after board service.

The 5060 bulletins apply to the earlier C750 and C76x platform. The Service Support Guide contains older model-specific tips, and each All Business Printers bulletin identifies the models or options to which it applies.

PDF Search, Bookmarks, and Wiring Detail

Text search and navigation: The service manual and service tips archive have searchable text and embedded bookmarks. The individual bulletins have searchable text and no embedded bookmarks. The three wiring sheets in the service manual have no searchable labels, and their small pin and signal labels are readable when zoomed in.

The ZIP contains 758 pages across 26 distinct printable PDFs, plus seven duplicate copies in the nested folders. The page total includes the service manual’s cover, publication page, appendices, defect-locator sheet, and wiring diagrams.

Print Engine, Paper Path, and Option Service

The selected topics below cover common bench repairs and diagnostics. The service manual also explains standalone testing of the high-capacity input tray and identifies lubricants for replacement drive assemblies.

• Fault isolation covers 100-series print engine faults, 200-series jams, 900.xx RIP errors, and 925–990 service codes. Symptom tables and checks cover the image transfer unit (ITU), fuser, printheads, power supplies, and paper-handling options.
• Component replacement covers the printheads, ITU, fuser, second transfer roll, autocompensator, vacuum transport belt, high- and low-voltage power supplies, and system board.
• Feed and finishing options include drawer and duplex tests, plus service checks for the high-capacity input tray, output expander, mailbox, and StapleSmart finisher where fitted.
• Electrical references include left- and right-side system-board wiring, high-capacity input tray wiring, cartridge-contact pin locations, and transfer HVPS and LVPS connector references.
• Parts and maintenance include exploded views, a part-number index, voltage-specific fuser kits, and scheduled ITU service.
• Field troubleshooting covers transport-related color misalignment, repeated or false jams, incorrect media settings, and printhead errors that appear after service.

Lexmark wrote the service manual for service personnel who diagnose printer faults, make adjustments, and replace field-replaceable assemblies.

Color and Electronic Diagnostics

Power-on reset checks, ITU belt tracking, registration and color alignment, and print-quality samples support fault isolation. For a missing or faded color plane, the Partial Print Test helps narrow the fault by comparing the developed image on the cartridge drum with the image on the ITU belt. The manual explains how to use the printer’s built-in defect chart. The separate defect-locator sheet is labeled for the C75x and C76x.

The diagnostic and configuration menus cover the display, buttons, DRAM, cache, disk, flash, sensors, and interfaces. They also provide event logs, page counts, size sensing, regional defaults, Auto Color Adjust, and fuser-count reset. The disk and flash sections identify the tests that can affect stored data.

The service tools list includes parallel wrap plug 1319128, twinax/serial debug cable 1381963, and coax/serial debug cable 1381964, along with a multimeter, feeler gauges, a spring hook, and standard hand tools.

Repair, Parts, and Configuration

The repair chapter covers covers and access doors, cartridge contacts and drives, the fuser and ITU drives, registration components, the multipurpose feeder, media-size sensors, and cooling fans. The parts catalog distinguishes components for 1xx/3xx and 2xx/4xx machine types and identifies hardware for specific feed and finishing options.

All four models have 500-sheet drawer and duplex coverage. The C772 and C782 sections also cover the high-capacity input tray, output expander, 5-bin mailbox, StapleSmart finisher, envelope drawer, outdoor media drawer, and banner tray. The C772 envelope feeder fits the C772. The C782 version fits both the C772 and C782.

The printhead procedure calls for mechanical alignment after replacement and specifies which electronic alignment checks follow. It warns against loosening more than one printhead at a time and against leaving the alignment fixtures installed. Bulletin C7xx_119 connects a post-service 10x.05 error to a reversed mirror-motor cable at the system board and identifies when both the printhead and board require replacement.

The service manual identifies high-voltage and hot-fuser precautions and specifies a three-person lift with options removed.

Fuser and Transfer Unit Service Examples

For fuser faults 122.05 and 122.06, the diagnostic chart gives approximately 0.13–0.64 V DC at system-board connector J17-11 as the hot-roll lamp cycles off and on.

The scheduled-maintenance chapter lists the fuser reminder at 200,000 copies for the C77x and 120,000 for the C78x. The ITU reminder appears every 120,000 copies, with the ITU and second transfer roll scheduled for replacement together.