CANON - canon lens 28 135

Comprehensive service manual for the Canon EF 28-135mm 1:3.5-5.6 IS USM lens (ref. C21-9931). This four-part technical document provides all information required for maintenance and repair of this professional zoom lens. Part 1 covers general information including development objectives, key features, complete specifications, external dimensions, and exterior design details. This section explains the optical image stabilizer technology and operational restrictions across different camera models. Part 2 delivers in-depth technical data: component listings and functions, integrated circuit pin tables (IC1 through IC12), circuit descriptions, zoom lens optical system explanation, and image stabilizer operation with functional principles and sequence. Part 3 contains repair procedures: disassembly and reassembly notes, expendable component locations, required service tools, and detailed adjustment items including tilt adjustment, focus calibration, zoom brush position, USM frequency, focus pulse adjustment, focus compensation, LED current data input, mechanical lock centering, gyro rank data, and gyro sensitivity adjustment. Complete instructions include adjustment software operation and connection procedures. Part 4 features a complete parts catalog with illustrated exploded-view diagrams and detailed component listing with cross-reference numbers for easy identification and ordering of replacement parts.