Phone is really hot after housing change

Hello

Changed the housing on my iPhone 5s. I've done a few before but not had this problem.

It's get really really hot. Even when it's turned off but still on charge

I've removed the motherboard and thinking I may have connected a cable wrong but to no avail

Also taken the screen off and then plugged it in to charge to see where the heat is coming from

It seems to start from the top right the section under where you connect the screen. Then the whole motherboard begins to get hot. I've tried to different batteries so it's defo not that

Can anyone help me please

Would really appreciate it .