Problem after changing charging IC

Hello everybody,

The iphone 6 plus battery started to drain, I tried everything from changing the battery and chargers to changing the U1700 ic chip which actually worked!

But unfortunately I couldn't connect it to a computer nor plug it in a charger, it works temporarily then turns off with apple logo loopinf when plugged in, i tried changing the ic chip twice and the problem hasn't been solved, anyone has any solution for this frustrating problem?