SPT - Citizen Shutter

This comprehensive service manual documents the Citizen shutter mechanism fitted to the Petri 7S camera, prepared for the Society of Photo-Technologists. It serves as an authoritative workshop reference for camera repair technicians and skilled enthusiasts restoring this classic focal-plane shutter. The manual includes factory shutter speed and synchronization test data across the full range from 1/1 to 1/500, allowing technicians to verify operational accuracy and identify performance drift. Detailed disassembly and reassembly procedures walk through access to internal mechanisms, removal of the photo cell, retaining ring, front cup assembly, scalloped ring, retard assembly, and time delay gear train. Annotated photographs clearly illustrate major components including the shutter speed cam detent, release lever, and photo cell contacts at each stage of disassembly, showing spatial relationships and proper component orientation. Specialized tool requirements and safe removal techniques for critical pins and mechanisms are emphasized throughout to prevent damage during service. This repair guide provides the technical depth needed for precision restoration work on this reliable shutter design.