Hello, I had half a year the problem that my radio has spun when it was cold. it just changed radio stations or has become quiet. Be the day before yesterday it is no longer possible. The display remains dark. If I also press power comes short the logo with premium sound but then it is dark again. Menu – Bass sound settings go. But no display to radio or CD. and there is no music. But what do I need to swap ? Control unit / amplifier or the original radio with 6cd changer ? THANK YOU