If there is no alternative I would go for that. Unfortunately all the cables are fit together now and it will be a bigger effort to separate them ....

I will continue on that by tomorrow. Thanks a lot for your help so far.

Cheers

There might be another way to test the amplifier of the ML/MCL converter, but for that you need a fully wired powerlinkcable. 

How would that go? I think  I can make me such a cable, latest by tomorrow.

Connect the powerlinksocket of your Ouverture to the powerlinksocket of your ML/MCL converter. Switch on the Ouverture and see if the converter also switches on. Reason for this test is that there is an NTC in the ML/MCL converter which switches the amplifier off when it is overheating. This NTC sometimes changes its value because of age. Because of this the safetycircuit thinks it is overheating and switches the amplifier off immediately. Another way of testing is connecting an ML IR-eye (round aluminium eye) to the converter and see if this will work. But for that you need the IR-eye.

I have to wait another day because the shops where I could get the cable rsp. plugs are closed on monday. Does it make sense to check the NTC separately?

I don't know how technical you are. You could simply disconnect the NTC, if the amplifier switches on after that it must be the NTC. Maybe another way of checking, does the ML/MCL converter switch on very briefly (led turns green and red directly after that) if you choose a source in a linkroom? And is the red led on on the IR transceiver in the linkroom?

I built some tube amps by myself so I know how to solder and basics about reading schematics. Unfortunately I have no schemytic for the convertor. How do I find the NTC?

The NTC is placed on a very small PCB which is screwed to the heatsink. 

Thanks so far. Have to make some days break on this issue due to travelling now. I´ll come back later.

I was happy.  yesterday because I found a broken pin in one of the connectors. Everything worked fine. Then I got call from my whife this morning - doesnt work again. Back to start.