After screen and dock replacement battery dies
I have an Iphone 7 which had a broken screen and the loudspeaker didn’t work. Easy repair because I fix Iphone’s for a quite long time. So I ordered every part I needed. After replacing the screen and loudspeaker the Iphone worked fine except the loudspeaker was still defective so I ordered a new dock because that could be the reason the loudspeaker wasn’t working.
After replacing the dock and putting the Iphone back, it got stuck on the Apple logo for 2 minutes and then suddenly it shut down. The red battery showed up with the charging cable, so I thought the battery was probably just empty. After charging the Iphone for around 10 minutes the screen suddenly became black and the Iphone didn’t respond on anything. Hmmm dead battery? I ordered an new battery and replaced the old one.
And after replacing the battery it started back up again but still stuck on the apple logo and then exactly the same thing happenend. The red battery showed up, I charged te Iphone but this time it turned black in 2 minutes I guess. So the battery dies completely if I put the Iphone on the charger.
What did I do wrong and is this possible to fix?