Just got this is, and in fantastic cosmetic condition. Power light goes on (blue); equalizer lights are on. i have my sub out to one of the line is; crossover set to bypass; volume set to maximum; phase set to 0. But there is no sound output. If I unplug the Sunfire sub, and plug in my Energy sub there is sound from the Energy sub. Can anybody suggest what may be wrong? I checked the fuse and it is fine