It's fixed

My Problem

Charging only worked while holding the lightning-connector in the right angle.

My Fix

60 Minutes sunday lazy afternoon work. Since it was my first iPhone-repair I felt quite unsure. Here the video was a great support. Unfortunately not every single screw is shown (e.g. step 19, step 24 or step 31 - rubber-micro-casing). Here came the photo-guide in.

Thanks to ifixit-crew for great support (video and step-by-step-guide)!

My Advice

Buy magnetic map to organze parts and screws.