W221 06 No Tuner No Sound

[MARCOSOFT]

I recently had a problem with this type of car. The audio tuner stopped working.
I checked it on the trunk, everything looks fine, I checked the specs and the actual configuration. But it's not fine, and of course I can't do anything about it.
Can anyone point out to me what I am missing or if this is a faulty device (amplifier/tuner)?

 

[EduardNN]

Does the diagnosis indicate a MOST rupture?
Open the tuner and check if the converter (SO-8) opposite the fan is rotten. Clean the tuner board from dust.

 

[julmari]

Basically, it looks like your tuner/amp got wet or something. Seen it. It's pretty common, and replacement parts, even used ones, are very expensive.