SPT - Gossen LunaPro Service

Complete service manual for the Gossen LUNA-PRO light meter, delivering the precise adjustment specifications field technicians need to keep this instrument performing reliably. The guide walks through all adjustment locations for both low and high ranges across EV1, EV7, and EV15 models, complete with exact adjustment values and step-by-step sequences that can be performed without disassembly. When internal service becomes necessary, detailed disassembly procedures provide full access to the electronic circuits, accompanied by essential safety information for handling PX-13 batteries. The troubleshooting section addresses real-world battery drain patterns typical of the instrument, helps diagnose needle stiction and galvanometer performance issues, and systematically covers the most common failures—dirty CdS photocells, defective galvanometers, and hairspring problems that affect meter response. Technical reference data includes photocell resistance specifications and galvanometer coil resistance measurements to support accurate diagnosis. Circuit board and component assembly photographs throughout the manual make identification straightforward and expedite fault-finding. Coverage of available replacement parts and procedures for exchanging defective assemblies ensures technicians can restore full functionality without unnecessary downtime.