Just picked up a second hand bass, tested it out and it was all working fine. And then I went into idiot mode.  I decided to switch out the volume knob, but the knob was really stiff and hard to lift off the bass (me being an idiot, I only noticed the little screw in the side afterwards). I managed to get it off... but something has come loose and now there's no sound coming from the bass at all. A few other symptoms... The volume knob just keeps turning now, it has no minimum or