20 - 30 minutos
The iPhone 3GS was shutting down abruptly multiple times a day. The issue was observed since the iOS was upgraded to 5.0 and later. It was consuming the battery at a rapid pace.
Overall the guide and video helped a lot. However I was not able to reconnect cable for connector #6 which looks a bit difficult or time consuming.
I was not able to fix this though!
I reconnected everything else and so far it seems to be working fine on the 1st day.
Be careful about reseating cable for connector#6. Even though this looks similar to #7 I personally found #6 difficult.