WiiU is stuck on WiiU logo. Is there anyway to fix this. Like a chip or new HHD or something?

Can someone please give me the steps on diagnosing an iPad mini that dose not power on.

There are many back glass repair services out there. They are usually inexpensive but you can do it your self. It is easier with a laser machine but heat could work to, but is extremely difficult and you may damage something in the process.

It may be that the battery is not taking charge thus when unplugged dies instantly.

You may have damaged the ribbon cable on accident when putting it back into the phone. it also might possibly be that it was not put in the correct way. I recommend taking it out and examining it and then making sure that the cable gets snapped into space correctly. if that doesn’t fix the problem maybe try using a different part. if that dose on work it may be a board or software issue.