I have a spider III hd150 head and cab, bought it new about 5 years ago. The other day i turned it on and theres no sound at all. Worked fine the time before that never had a problem with it until now. Everything lights up, all the fx knobs function, tap tempo functions, but no sound when i play. When i turn the tuner on it still picks up the guitar signal and i can actually tune the guitar with it, but yet theres still no sound. speaker cables are good and seated well, tried diff. guitar cables and still no sound. Any help would be GREATLY appreciated!!!!