I changed sd card, I blowed in harmony, I flashed the bios (pal50 & pal 60) on different sdcard, I tried several insertion position, and finally tried with original game centiped to test the hardware and it works perfectly (guenuine atari vcs 2600 junior pal).
I did not open the harmony because I don't understand how to and I don't want to break the harmony cartridge.
It stop giving video signal while running although the rom was still running (could hear the sound).
since then got crappy video signal or black screen. The crappy video rendering is basically because I believe the pins where not touching each other.
I could open it and solder sensitive part if only I knew how to open it and if I would have been sure that this is the problem !
any hints ?