Seiko Y301A, Y302A Parts Catalogue and Technical Guide

Complete parts catalogue and technical service manual for Seiko quartz watch calibers Y301A and Y302A. This workshop reference provides everything needed for professional repair, maintenance, and calibration work on these movements. Detailed specifications cover both case sizes (Ø20.0 mm and Ø23.0 mm) with 1.8–1.9 mm height and 3-jewel construction. Exploded parts diagrams with numbered components show exact placement and relationships of all internal elements. Step-by-step disassembly and reassembly procedures guide technicians through safe removal and reinstallation of movement components, supported by specific lubrication instructions using Moebius A and SEIKO Watch Oil S-6 at designated points. The circuit block structure section explains electrical layout and component function. Precision timing adjustment relies on the 10-second gate measurement method, with pattern cutting system details for frequency fine-tuning and temperature-compensated timing specifications included. Battery compatibility information lists genuine SEIKO SR716SW cells along with equivalent Maxell and Matsushita alternatives (1.55V, approximately 3-year service life). Technical remarks throughout address critical disassembly and reassembly considerations to prevent damage and ensure proper function after service.