Cadillac Repair: Electronic Dash on 86 Deville Coupe, blown fuses, watt amp

Question
My son bought his grandfathers 86 Deville, mint with only 51000 miles on it. For sdome reason he decided to install an aftermarket stereo with 700 watt amp, etc ( He did this while I was not home). While test driving the car after hooking everything up, the digital dash suddenly went out. They feel it has something to do with alternator, I am not sure, as everything else works. There do not seem to be any blown fuses, though when they were hooking up the stereo, they added a higher fuse for the radio. Any idea's? Hopefully he didn't mess it up to the point he is looking at a huge repair job.

Answer
He messed it up and is looking at a HUGE repair bill as the factory radio has 3 different voltages (5 voltrs, 12 volts and 16 volt lines going into the radio.

He most likely used a TEST LIGHT to find his power source and blew the transistors out of the instrument panel when he stuck the 5 volt wire with the test light.


tom