***[link|https://www.ifixit.com/User/4259144/Lakshya+Rohra|Lakshya Rohra|new_window=true] ***if this phone still has the original battery, you want to start with that. This "turned off after 5-6 minutes" is a sign of a battery that no longer holds a charge. Use something like [https://www.youtube.com/watch?v=5GH7i9QYGcA|this video] to get it done. It's a slightly different model but works the same way. Once you have the new battery, re-evaluate.