I bought a used Pitchblack off eBay, but I'm having a bit of trouble with it. I'm using a 1spot power adapter, and when I plug in my 1/4" cable I get a 0 that flashes a couple times. When I hit the switch, I get a solid red light right above the switch. Seems about right. But then when I play any open string, all I see is either a B or an A# on the tuner, as if it's not registering any real input from my bass. If I turn the volume knob on my bass all the way off, I'm back to just the red light above the switch. Does anyone know what the issue may be? Am I doing something stupidly wrong? Do I need a new battery for my bass (EBMM SR5)?