It seems to be a problem with voltage (because everything is fine with Lyon adapter module).

I'm not sure whether München "S" boards exist... But I think: no.

That's why I guess the problem is with the external voltage of 5V. You should use a power adapter which delivers 8-9 Volt or more. Inside the München board there is a 5V voltage regulation unit. It can not work with 5V from external plug because it needs a voltage difference of minimum 1V to control the voltage of the modules...

"Plus" has to be inside the plug! And "minus" is outside. HGN 5001 or something like that is fine. It doesn't has to be regulated.