Unresponsive iPhone 5 Please help

I am a Rookie tech working as a technician for 2 months and i replace parts in all types of iphones all the time with out a problem until now.

The phone had a bit of water damage near the connection to the battery just ail corrosion and that was resolved by the cleaning cooking process.

I replaced the lightning connector in the iphone 5 and i tested it to make sure that it was functional and it was everything was going according to plan until i reassembled the phone, screws, shields everything.

Placed the screen in and attempted to turn the phone on and nothing happened. Plugged it into my laptop and it does not respond. I held the home button down and it went into recovery mode ( DFU MODE NO DISPLAY) . It can not be restored it gives me multiple error codes.

I tried cooking it again and nothing worked

Now the phone doesn't even want to go to recovery mode and i am stumped.

Can someone please assist me with some useful information and i really don't want to hear that i short circuited the board because im going to replace the board and thats 200 gone

Im a fan of ifixit you guys are the reason for my career choice.