Electrical problem
2005 Nissan Pathfinder 6 cyl Four Wheel Drive Automatic 115000 miles

My pathfinder started to have intermittent stereo problems when one day the stereo system would work great and then the next day it wouldnt work at all. Sometimes it would come on during driving just out of the blue. It doesnt seem to matter if I run over bumps, ect. Currently there is no sound but everything on the radio seems to work as normal. It has not been coming back on now.

What could it be. I have heard of people replacing the amplifier but I dont want to spend $500 unless if I absolutely have to.