no power to stereo

[oilburner23]

So i pulled out my aftermarket pioneer head unit on my '94 F-350 and was putting it back in and it wouldn't power up at all or would sporadically turn on then off. I connected the yellow and red wires and it turned on. then after I saw a spark and now the pioneer radio wont power up at all. None of the fuses in the fuse box under the hood nor under the steering wheel were blown nor the one on the stereo itself. I bout a new stereo just to make sure it wasn't that and the new kenwood one wont turn on at all either. I'm lost and have no idea what else to do. I tried disconnecting the batteries to possibly reset it but no luck. Anything will help.
Thanks