This clip is not available for purchase so if you break it you'll have a problem. Try some tape to hold the cable in place don't use force. Many ppl broke their board just because they fucked up that clip.
Still the same problem after double checking all the connections. The touchscreen connection does not seem to be the problem, because there is no sound when it turns off and the touch screen is blue for a second (you can even see the code in white letters). It just turns off a second after turning it on. I am so close...
It worked!!! I am so happy right now! After disconnecting and reconnecting every single cable, as well as solving some more problems I finally managed to restore sysNAND and emuNAND as it was before the brick.