Red screen after screen replacement

Hey.

So i’m have encounter a problem that I never seen on iPad mini 4, been doing these repairs for a couple of years but never seen it tho.

Did a screen replacement for a customer, everything went fine. But when i’m trying to start the iPad , straight after apple logo i’m getting a red screen. Then it just reboot itself. I have tryd with several differents screens and checked HB flex cables. I also checked the surounded area around the display connectors on motherboard to see if I have touch anything these. But cant see any damage at all…

This iPad was working fine before the repair and it doesn’t work anymore with the original screen or the new ones. Just getting red screen all the time..

So my question is if someone have encouter this before and know what I should look after? I have a friend of mine who can do some micro solderning and I have some knowledge about it but cant really do it. But I’m guessing its a motherboard fault.

And yes I did remove battery before removing screen etc.