Audio Systems: Stereo lights up but wont play or eject cd., radio connector, connector block

Question
Hi,

We've just had to mess with our car battery and in the process seem to have done something bad to our car stereo. We think we shorted it.  It lights up, but won't turn on or eject the cd that's in it.  We checked all of the fuses so are guessing it must be the wiring.  Do we need to take it to a professional or have we damaged the stereo beyond repair?  Thanks.  

Answer
Hi Melisa,
What can one say, ooops?
I think yo may have fried it, did you jump start the car at anytime? That kills more electrics’ than any other single thing.
Use a tester and check for BOTH 12v at the radio connector block, 12v perm and 12v ignition (acc) if both are ok then if the radio is under three years old and worth more than $150 then repair is worth while, otherwise bin it and lesson learnt, buy a new one.
Good luck, Peter
p.s. don't forget the feed back so I know how I'm doing, thanks.