Jbl mr 145.2 will not turn on - JBL Boating

SOURCE: I have a jbl mr-145

I have the same model stereo in a brand new hot tub that was having the same issue. To fix it all u need to do is pull the front cover off to access the pump controls and in there you will find a black box where a power cable runs yo the stereo. There are two screws that open a little door in the black box. In there you will need a small flat head screwdriver to move a redswit over to the 110 volts position. Turn the radio on and it should work. That black box just controls the power to the stereo.