i purchased this voltage converter regulator from amazon DROK® DC Volt Converter Regulator 8-35V 24V/12V to 1.5-24V 5V 12 V 5A Adjustable Voltage Module
by DROK
i am installing in a 24volt dc application it puts out 24 volts but will not adjust down voltage with set screw, anything im missing or is this just defective