No I tried it with my RGB cable only and i think the cable does work. I get the start screen and cybermorph runs in a demo after that. But I could test with RF of course.
Yes I plugged all 3 Controllers straight into the console Port 1. I tried also Port 2 and with Team Tap but that was more kind of despair.
On my research I read it could be an issue with the ICs U20, U21, U25 (74HC244) but I dont know which things I have to measure for finding it out...
ICs are looking okay and dont warmup or such things.