Well, had it checked by a repairguy. An honest one, that is ;-)
The good news is, it was just the fuse. She's running again.
The very very bad news is that the fuse that burned was a 15A fuse. There should be a 10A fuse in it.
His words:" the inner of this engine is litterally taped together and I don't know where to start to check things out. Everything seems even rotten".
It's not that he really does not know of course, it's more that he cannot give any guarantee to find the culprit quickly and he advises not to spend any extra money on this bike since he does not know where it ends.
So, that was a very short lovestory of me and my vn750.
I think the only option left is the see if someone is willing to pay a few bucks for a projectbike.
I'm sad, because I loved the way it rides, but do not have the money at the moment to get another one.