My radio - 92 vette - just started acting up. I keep it on a battery tender for the winter and just started using it for the first time in a couple of years. The radio whines and squeals from time to time really bad. It started ( I think ) with a low level condition first day i.e. it sounded like the bass was missing. I put a CD in and it seemed to fix it until the squealing started. It is very annoying and I was wondering if it's a Radio issue or a wiring issue. Thanks for any help!