Screen not displaying anything but still working.
My iPad pro display nothing while and after reboot or recovery mode. I plugged my iPad to PC and I can see my iPad screen Touching is working and voice over is still functional.
quite important question: did it happen after screen replacement or fall? Of course, sometimes the screens also stop working by themselves, but that doesn't happen often. We need to find out what the last moment of a working tablet was. If this cannot be determined, you will need to seek the service of a professional technician.
In your case, the tablet works without turning on the screen - look at it in a dark room. Is there a slight illumination from the LCD backlight? The answer will narrow your search a bit.
ahead of time (for other readers): if this happened after screen replacement and the backlight works. Another question: did someone disconnect the power from the motherboard when replacing the screen? If not, we are looking for burnt induction parts near the video socket. If so (I always assume that if so, he did it wrong - it only applies to tablets), we are looking for video signal paths on the motherboard. Unfortunately, in both cases it cannot be fixed without microelectronics equipment and without much knowledge of the subject. Rather not for home repair.
Your LCD, may be broken . You would need to buy a new LCD or send it to Apple