I just bought a Boss ODB-3 pedal off of a friend. I tried to play through it the next day, and it wouldn't work! The on light comes on, but I can't hear any difference in my sound. I tried turning all of the knobs and the only one that seems to change my sound at all is the level knob, and it doens't change very much. I was expecting some distortion, I'd heard these things can sound pretty raunchy, but this thing does nothing. I checked to make sure the cables where plugged into the right places, and still nothing. No overdrive, no distortion, no boost of any kind, nothing. I trust the person I bought it off of, like I said, it's my friend, so I doubt he would sell me a broken pedal. Any suggestions? What am I doing wrong, or what's wrong with it?