To assist instrument mechanics of higher classification in locating and correcting trouble in control systems and instruments of combustion equipment and nuclear reactors, turbines, chlorinators, water treatment systems, and station auxiliary equipment, involving inspecting, cleaning, calibrating, replacing defective parts, and repairing electrical and mechanical instruments and controls. Acting under prescribed rules and approved practices, to assist instrument mechanics in locating and correcting trouble in generating station mechanical and electrical control systems and instruments; to inspect, clean, adjust, calibrate, and repair assigned instruments and guages; and to perform related work as assigned.