Not powering on or not seen by iTunes. Replaced battery.
I had the iPhone 6s Plus since new over 4 years ago. The screen went black while using it with plenty of battery left and won’t power back on nor did iTunes recognized it. I even tried the soft reset by pressing the home and power buttons for a few seconds with no success. The original battery was less than 80% of max capacity. Replaced the battery with the iFixit part with the same results of not powering on. What else could be wrong with it?