LCD goes dark after start up.

Hi!

I am having an issue with an iPad Air, after it starts up the screen goes dark and won’t light up again.

This is how it goes:

-Apple logo shows

-Apple logo dims down slightly

-The iPad starts up still dimmed down, but you can clearly see

-After 10-30 seconds the screen goes dark and when you press the power button nothing happens. I tried holding the power button, it does not starting, but holding the home and power button does restart it and the screen turns on for a few moments again.

I have no idea what’s going on, and I have already tried a new LCD, same problem.

At first I thought it was the backlight as the LCD shows a “wave pattern” of light in the upper left corner. But the new LCD does the same thing.

Tried holding the power button does not starting, but holding the home and power button does restart it and the screen turns on for a few moments again.

Anyone have any idea?

Can a damaged battery cause this? Like if the screen doesn’t get enough juice or something?

Thanks in advance!