Arriving to the Mare Island Navy Yard in California in October 1940, Chandler was converted there into a destroyer minesweeper, and was reclassified DMS-9 on 19 November 1940. As part of her conversion, her number 4 boiler, her fourth funnel, and her torpedo tubes were removed, her depth charge racks were repositioned forward from the stern and angled outboard, and her stern was modified to support minesweeping gear, including davits, a winch, paravanes, and kites. Two 60-kilowatt turbo generators replaced the three original 25-kilowatt electric generators to improve her capability for sweeping magnetic and acoustic mines.