when the wax motor blows it burns out the resisters in the board. If you fail to replace the wax motor then every board you put on there is gonna blow. The way I understand it is when the wax motor is good it locks the lid. When it goes bad instead of it preventing power to the board it bleeds voltage to that board, frying it. When it goes out then it allows full fledged 120 volts to go into the board and frys it.This is a defect . Later models have been modified with better wax motors. They have a different color to show the modified version.