millersoviet

A couple of weeks ago I fitted a forester pocket with great success, this involved taking the stereo out and drilling some holes in the housing plates and then fitting the pocket. After putting it all back together I went to test the stereo and was greeted with Alternator whine. I only unplugged the stereo and plugged it all back in, I have not rewired anything, I just can't understand what could of happened. Anyone with any Ideas?

I have since re-earthed and tried new phono leads to the amps, the whine is still there.