I got a new-to-me Mercedes MC3198 (A 002 820 7989) 6 disc changer over the holidays. Plugged it in and the head unit recognises it, but reports
"no cartridge". Also can't eject the cartridge that is
currently inside it.

this is the 2nd unit that I have had this problem with it, which leads me to believe that either this is an incorrect application for my car (99 E320) or that something is wrong with the wiring or my head unit.

anyone ever experience anything like this or have a clue where to start investigating this? Anyone have the pinouts for the power connecter?

thanks!

jeff