lol i did something similar. I tried tightening my sub lines with the amp on and blew my cd player. the best way to check is to wire them up to another car. But, in your case they are immobile so I geuss if you wanted to just unscrew them and try to plug them in somewhere else
Almost impossiable to blow your head unit unless you hooked the wire up to the frame of the unit (depending on unit type) Does it smell like burning hair? Then you blew it otherwise all you did was blow fuses in your car.