Ipad Not powering on after screen replacement

My iPad worked perfectly fine but the screen had a small hairline crack so I replaced the digitizer and when I tried to turn on the iPad after I finished it didn't boot up I checked to make sure all the cables are connected and the screws are I've tried connecting it to iTunes and nothing shows up. I think this is because I forgot to turn off the iPad before the repair also when the iPad is charging I can hear the motherboard making a high pitch noise it gets louder the higher the power of the USB is it is barely noticeable when the iPad is connected to a usb 2 port but it gets a bit louder when connected to a usb 3 port.

If anyone can help me that world be amazing

Thank you