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.

That system has problems with electrolytic capacitors that dry out (and sometimes physically leak). It may not be the CD but the tuner module that is bad (mounted in the trunk with amps). Some time ago I repaired one for a friend that would pop when the volume was adjusted on some functions (it didn't have a CD). Turned out to have quite a few bad capacitors in the tuner module. Replaced all bad ones and the quality of the audio improved dramatically as well as no more pop.

Thanks Rick, I appreciate the reply.

I guess I'll try and find the amps/tuner module,,, I didn't even know my car had a separate amp!

Is this gonna be a dealership thing? I assume I can't trust Circuit City etc. to fix something like this?

Juck,

The tuner and amps are located behind the right side trunk carpet panel (on the w124 sedan - not sure if same location on the cabriolet). Easy to remove the tuner - 10 mm headed bolt goes in the bottom of the bracket. Remove it and the tuner slides out of the bracket.
You might look for a dealer (or independent) that has a test unit that you could plug in to find out which module is at fault. Very quick job to hook another one up once you have the carpet out.
Do a search on this forum for 1432 and you'll get some more reading.