Canon Pixma MP620 / MP620B Service & Repair Manual

This four-file Canon U.S.A. factory set covers the PIXMA MP620 and MP620B inkjet all-in-one printers. It is suited to experienced printer technicians and repair shops comfortable with mechanical teardown, electronics handling, EEPROM work, and Canon service-mode software; it is not an operator guide or a beginner repair manual.

• 57 PDF pages across four files: a 47-page 2008 Service Manual, a 7-page 2009 Parts Catalog, a 2-page Service Information Notice 5709, and a standalone 1-page copy of Notice 5712. The 47-page service-manual file contains 44 numbered service pages plus its cover, contents page, and an embedded copy of Notice 5712.
• Error coverage connects LCD messages and Alarm/Power LED blink patterns to fault conditions and checkpoints for the carriage and line-feed encoders, purge and ASF mechanisms, APP drive, ink absorber, print head, EEPROM, USB host, scanner, and network hardware.
• Repair sections document removal of the external housing, scanner and document cover, operation panel, print unit, logic board support plate, ASF unit, carriage, spur and platen units, plus the purge-drive and switch-system assemblies.
• Factory adjustment coverage includes EEPROM initialization and destination settings, ink-absorber counter reset or value transfer, LF/Eject correction, ink-system checks, button and LCD testing, print-head alignment, paper-feed motor positioning, grease application, and wired/wireless LAN reset.
• Post-repair checks cover EEPROM and service-test printing, nozzle patterns, copying, USB printing from both paper sources, PictBridge, IrDA, LAN/WLAN, Bluetooth, Scan-to-Memory, Card Direct operation, internal inspection, and transport preparation.
• The parts catalog supplies 12 exploded-view figures with exact callouts for assemblies such as External Covers & Scanner Unit, Logic Board & PE Sensor Board, Sheet Feed Unit, Carriage & Pressure Roller, Platen & Spur Unit, and Purge Drive & Switch System.

Error Diagnosis and Symptom Coverage

The service manual separates operator-call errors, service-call errors, other LCD messages, warnings, and symptom-based troubleshooting. The tables cover rear-tray and cassette feed faults, paper jams, ink-tank recognition and position errors, print-head faults, ink-absorber status, scanner time-outs, carriage and line-feed errors, purge and pump sensing, EEPROM and logic-board failures, USB overcurrent, drive-switch faults, flatbed motor errors, and wired or wireless network problems. Checkpoints identify likely contamination, cable, sensor, mechanism, board, motor, or assembly causes instead of listing codes without repair context.

The symptom section also works from the complaint backward. It addresses no-power and sudden shutdown conditions, abnormal noise, LCD faults, misfeeds, poor scanning, missing color or white lines, paper smearing, enlargement in either carriage or feed direction, and failed network printing. EEPROM information printing retains the recent operator-call and service-call error record for bench diagnosis.

Disassembly, Adjustment, and Verification

Mechanical repair coverage follows the printer from the housing and scanner down to the paper path and drive assemblies. Cable-routing views support the right-side harnesses, ink-sensor and WLAN wiring, and left-side ground cable. The embedded Service Information Notice 5712 revises the print-unit and logic-board material with added support-plate and cable-guide removal instructions.

Logic-board replacement receives a full initialization sequence rather than a simple swap note. The manual identifies the required EEPROM, destination, absorber-counter, ink-system, LF/Eject, panel/LCD, print-head, language, and network operations, followed by functional verification. The procedures require Canon's computer-based Service Tool, which the manual says operates only on a pre-registered computer; the PDF set documents its functions but does not include that software.

Parts Identification and Repair Cautions

The catalog ties the exploded views to service part numbers, including the QM3-3716-000 cassette unit, QY6-0073-000 print head, QM3-3679-000 logic board assembly, QY5-0235-000 absorber kit, and QM3-5031-000 purge drive system unit. It also distinguishes MP620B-specific exterior parts. The grease chart identifies FLOIL KG-107A, tool No. QY9-0057-000, for the carriage rail, related sliding points, APP code-wheel gear shaft, and Easy-Scroll Wheel base.

Notice 5709 documents a service trap affecting the MP620: an ink tank can appear installed while sitting too high at the rear, allowing it to strike the main case and produce a 5100 carriage error followed by C000 after a restart. Carriage repair also requires preservation of the original rail position and protection of the timing slit films from grease, scratches, and bending, since those films provide carriage and feed-position feedback. Before internal service, Canon calls for removing the power cord, allowing approximately one minute for capacitor discharge, and using static precautions around the logic board, LCD, scanner, sensor, card, and WLAN electronics.

The set is focused on mechanical disassembly, assembly-level replacement, adjustment, error isolation, and parts identification. It includes cable-routing and connector-location material, but no component-level circuit-board repair chapter or electrical schematic set.