Whatever you do don't touch the master faders!
About to go on holiday and made mistake of logging into the servers to check the Live Day was going out all right. Panic - missing a channel. We only broadcast in mono but all sound up to point of transmission is in stereo. I couldn't get into the studio but left a message with our other main tech support Ken. Then had a thought - perhaps I'd better call the studio - nothing like doing the obvious. Are all the level meters moving no? Are the master faders all at the zero level point ? No! Can you move so they are all the same - problem solved. Someone had moved master fader to zero instead of leaving well alone. Whats the moral of the story? If you can move or twidlle isomething that shouldn't be moved or twiddled then someone will do so!