Ben simpson

Hi.
I am in the process of fault finding for what I think is a packed up dab antenna amplifier for the c204 coupe. I have found one that has a2048200189 on it and think this may be what I need to replace. I have checked the fuse and power to it. Mercedes diagnostics have told me the amplifier has failed, but before I go replacing this, I wanted to make sure I am replacing the right one. I found a a2048200189 which attaches to it. I suspect this may be in charge of the roof shark fin antenna but don't know for sure. A while ago I found a detailed diagram of the wiring and dab antenna and amplifiers on here, but the life of me I cannot find it again. I have spent a few hours on Google but seem to be wasting my time.
Does anybody have a link or a page heading where I might look?
Also can anybody confirm if it is only the a2048200189 responsible for the dab antenna or the other one plays a part in the signal too.
All advice and help appreciated.
Many thanks.
Ben