CPU hot even when screen is disconnected( Black Screen)

I just replaced the whole assembly with the frame, lcd, and screen all in one. took off old and put in new. i didn't put the metal cover back over the cables connectors once i fixed it so i know it does not have the Long screw damage. The screen turned on and worked all day long! then after about maybe 8 hours later. it just went black and the (im just guessing here) but it gets hot right underneath the cable connectors for the screen which i believe is the CPU. so now i put the old screen back in to make sure the screen wasn't the issue . it was still black and still got hot on the old one. also plugged the battery back in after it cooling back down with no camera or screen attached to the connectors and when i plugged the power back in. the CPU still gets hot. so i do not know seeing how i dont believe to have long screen damage . and it still gets hot even without the lcd connected. IM LOST! and i do not know what else to do.