Here is the happy ending:
Well, back to the LS150s
After installing 2x 4 brake modules, I sat downstairs and watched the mess of wiring and then shut down our only AC transformer supplying the 18 LS150 + power to the drives & signals + lights in e.g. signals & lanterns …..
It went through my head - What have I connected incorrectly and thus made a short circuit!
But before I could get up, the power came back on, and after a short period it disappeared again. I then stayed a little longer and watched several outcomes before I had to turn off the power.
My conclusion – overload – so I bought an AC transformer (Art. 60032 with 32 VA) similar to the old one and had the track split into North & South.
The power outages had created 10-15 different "wanderings", both switches that switched incorrectly, but also that gates suddenly jumped from one box to a completely different one.
Before switching to 2, I also measured the power consumption of the first transformer in idle mode, and it was approx. 1.8 amp.
During that period, I also had contact with Erik from the website
https://www.jphobby.dk/bane/index.html, so he got the story, and he offered to join and try to solve the problem.
The LS150 is described here:
https://www.jphobby.dk/bane/dig-ls150.html It turned into a lot of emails, where I was given homework, all of which consisted of creating documentation for each port standing up (which I had most of) and review of each port's setup, because the track works with different drives. Magnets such as Märklin Art. 7549/75491 & motor-driven MTB mp1, and thus also different impulse times, where MTB is just under 2 sec. for the movement so it is set to 2.0 sec and Märklin's default was 0.2 sec.
It was also explained to me that an LS box had a memory so that a port had to be changed before the change of the next one started. BUT that the memory didn't wander on to another box, so it made me change the impulse time on the CS3 to 0.22 for the Märklin drive / Viessman magnet signals / brake modules + 2.2 MTB drive.
So in the end I was "released" by Erik, as he thought that it should now be able to work.
However, I have bought another 60032, which is now only connected to the 18 LS150 …..
And since August there hasn't been a single error.
I am convinced that it is overloads that made the errors. Before the big crash, I have also seen prints out of the corner of my eye before, which have suddenly flashed due to of that overload, but I just haven't understood why.
So it is the first x-stra transformer that solved it!
The original AC transformer was the power supply for the LS150s, and thus indirectly supplied power to various drives + lights in lanterns & signals + various overpass barriers, etc., and it never occurred to me that the LED + other things next to it drew so much "power".
So this long journey of suffering for you & me is over, and good thing I stuck with LS's and didn't switch to m83, of which I had bought 3!
And not least that I got good support this summer from Erik - he has a lot to thank for that.
"Snap Snap Snude" ( a danish phrase ) and now that story has ended well …..