I don't know the first thing about car audio,, so please bear with me.

On my 93 300CE Cabriolet, (Factory Becker & CD Changer) there is a single loud POP sound from the speakers whenever I click the Volume control UP or DOWN. There is also occasional (seemingly random) popping during CD playback.

This only happens when I'm playing CD's ,,,, Cassette and Radio work fine at all volume levels,,, no popping whatsoever.

Is this a known issue with these units? Anyone have any suggestions?

Just figured I'd ask before I go ahead and buy a new CD unit.

Thanks in advance.