Black screen on startup only when plugged in wall adapter
My iPhone 6 does not work anymore, when I try to start it it does not do anything, and when I plug it to a wall adapter it start, I have the apple logo, then a black screen (But it does not start when plugged to my computer with USB).
I tried to replace the battery, and it starts even when not plugged, but with the same issue (black screen after apple logo). I tried to restore it but it did not work, and while I was trying to figure out why, it switched off. And now it is the same as before, it only start when plugged to a wall outlet...
I tried to lauch my iPhone without the battery connected, and I have the exact same thing...
Anyone knows what can be the issue ?