Hello everyone. So as I said I got another wii, got it trimmed and tested, everything was fine, but as I installed it in the shell... nothing changed.
The restart issue was still there. Just like the previous wii it "worked" for like 30 mins, I was able to play something although the video signal was bluish and there was no audio from headphone.
After some swears ad cursing the day I came across this site I think I finally found the problem(s?): I changed a voltage ground wire position from one of those gold screw holes to the one in the 1,15v component, but more important I got rid of the battery cables which were too big and damaged and I changed with some better ones.
Now it works like a charm!!
Then I moved the rgb cables to the downside of the mobo and fixed the blue tone image too! (It simply was the ground and data wires inverted of the red cable

)