My replacement LCD is not showing ANY image, NOT a backlight issue

Hi there, I am a repairer down the bottom of the world in Wanaka New Zealand and i have a very peculiar issue.

I have just replace the LCD on an Ipad Mini 3 as the original cracked whilst removing it. Clumsy accident but one I fully own as my own fault.

I was doing a battery replacement.

The new LCD doesn't work at all. So I test the old broken screen and it works fine (apart form the cracked screen, I can see the Apple logo and the ipad boots fully.

I disconnect the battery and remove the old LCD and reconnect the new LCD and reconnect the battery and... Nothing.

I have tried a hard reset, nothing, I have put the old LCD on again and it is fine. I have also tried three other screens, old and new, nothing. Only the original one works???

Hellllllllllp!