Chosen Solution
I just replaced an iPad mini screen and LCD. The display keeps flickering black. If I hold the power button it turns back on and shows the power off and the display. It seems that the new screen I put on is defective and the digitizer isn’t working, but that shouldn’t be affecting the LCD. I checked and made sure it’s connected fine, and it is.
Was the battery disconnected when plugging or plugging in the screen display? If not, the backlight filter may be blown and needs to be replaced. This can be confirmed by trying the old screen and/or shining a flashlight on the replacement screen and see if an image can still be seen but very dim. The logic board can be repaired by someone reputable that is experienced in micro-soldering / board-repairs for iPads. You may find someone locally that offers this kind of service.
Do check the cables when you connected the iPad LCD screen… I do agree with ben but be sure that you have connected the LCD correctly placed in the socket, because sometimes we accidently make mistakes when replacing LCDs on our devices… right? The way I do it is not put pressure in the middle of the socket but rather start by pressing the sides gently (right - left)… I did screen replacement when i was entering smartphone repairing industry and mostly failed miserably because I damaged the socket by exerting a little force when connecting screens.
