CANON - Canon AT1 Service Guide

Comprehensive service guide for the CANON AT-1 (C12-1501), the second-generation camera employing revolutionary production techniques pioneered by the Canon AE-1. This technical manual documents the key differences from the AE-1 model, emphasizing the match-needle exposure determination system with extended measurement range. The guide provides thorough technical specifications covering: camera type (35 mm focal-plane shutter SLR), format (24 x 36 mm), interchangeable lens systems (FD and FL), viewfinder design (fixed pentaprism without condenser lens), electronic shutter speed control, and TTL exposure metering with central emphasis sensitivity. Major sections address disassembly procedures (top and bottom covers, electric parts unit, film counter mechanism, front panel assembly, shutter speed selector), assembly and adjustment protocols (match needle stroke adjustment, tension compensation, tungsten wire routing, maximum aperture correction), and systematic troubleshooting for operational failures. Detailed adjustment procedures cover exposure meter deflection verification, battery checker calibration, and meter accuracy testing across multiple brightness levels. The manual includes complete electronic circuit schematics with comprehensive pin descriptions, functional explanations of the timing circuits, and detailed operation sequence analysis including Speedlite 155A flash synchronization capabilities. A valuable reference for technicians requiring in-depth knowledge of the AT-1's mechanical and electronic systems for professional service and repair work.