I picked up a cube GX10 in the discount bin at a pawn shop, For $10. It didn't have a power cord, but I have a bunch at home. I found one that would work. Here's the problem/question: It powers up, and can't be turned off with the power switch. (It stays on until unplugged). 2nd... I get no sound, I've tried plugging in a guitar, mp-3 into the aux, I get nothing. Yes the speaker is hooked up. When I unplug the power I get a pop through the speaker. Any ideas what the problem could be. I'm not an electrician at all.