88 chevy celebrity head unit problems

Hey there. I just bought a 88 chevy celebrity. I took out the factory HU and installed a pioneer cd player. But lo and behold, it doesn't seem to be getting any juice. I thought, well, maybe it's broken, because I've had it for a couple years and pulled it out of 4 different cars in the meantime maybe it was mistreated (my old roommate liked to ruin my stuff..) So I go ahead and put in the factory (trust me, I've checked and everythings been wired correctly.. I've done it a buncha times) and all it does is buzz. The clock/display part doesn't even light up, but the rest of it does (IE the power button). It sounds like it's stuck in AM, but I don't think so, it doesn't tune to anything, and I know the antenna's in. Well, I guess I'm just frustrated.. wondering if anyone could give me some insight. I'm no expert but from what I've seen on here you guys know your stuff. Oh, and I checked, it's not the fuse. Thanks a lot for reading, and I appreciate any help. -a kid who needs music to cover the mechanical inadequacy sounds in the car-

test all your power/ground wires. then check speakers. you should be able to isolate the problem there.