Obtained a used Marquette chest freezer that is not cooling. I have no idea how old it is, but the compressor # is F118188. When I plug it in, I CAN hear humming like something is working, but it was plugged in for 15 hours and is still the same temp as the outside area. If I turn the knob off, I can hear the humming shut off and it starts again when I turn it on. What I am not hearing is a compressor kicking on and off, so I am trying to find out the problem. We were told the freezer was in working order when we got it.