Replaced broken and then tablet died

Hey have a sad story.

Replaced a broken but working screen. Connected it and turned it on, all worked good. Continued to then add the double sided tape and closed it up. Went to turn it back on. Nothing! Opened it back up again, checked cables etc. still nothing. So then I thought maybe the battery shorted. So I take of the plastic frame and unplugged the battery from the motherboard. Then held down the power button to clear any remaining charge. Plugged in the screen again. And it was back on! Great!

Put the frame back on. And then it goes dead again. (Doesn’t turn on or charge) So then with some playing I notice that if the charger is in but the battery was disconnected then I get the lightning in a circle on the screen. Then I reconnected the battery and nothing happens and now from this point nothing I do will make it do anything. tried checking all the connections, nothing on the boards that looks broken, there was no sound or pops etc

Anyone had this before? And if so was it the battery that was to blame?