I went to turn unit on this morning and it would not power up. When I got home, I checked the fuse it's wired into and it was ok. I then checked the small 15 amp fuse in the back of the unit and it too was ok. I then checked the power supply wires and they both were live. What else can I check or is the unit dead? I've only had it for about 15 months. Thanks for any help.