I've got a problem with my Mesa Big Block Head and I'm hoping someone could clarify me a bit about what might be going on inside there. Symptoms: - The sound fades in and out, but comes out of the cabinet - Sometimes the signal goes as far as the dedicated tuner out, sometimes even it doesn't get a signal. (If I recall correctly, it should be right after the input in the signal chain) - The foot pedal ceases to work all of a sudden. No mute, or changing the channels. The indicator lights go out, so it doesn't get a signal either. I've checked the cab & instrument cables, they're ok. Bass also works without a problem (not even a hiss) I guessing it could be a connection problem with the input plugin, or some other bad connection in the signal flow (the pre tube maybe)?? All help is appreciated.