20 - 30 minutos
My phone issues began with what I thought was a simple attitude problem...seemed to power down when I would leave it in camera mode for an extended period of time. In the beginning, I was able to power it back up unassisted from external power. I assumed it was the camera, so slowed my usage. Eventually, it began powering down when using the web browser or checking email, twitter, fb, etc. It was when it began interfering with my 4 year old's Netflix time that I knew the problem was more significant than just the camera; I think I knew it before this time, but I didn't want to deal with the complaining from the 4yo on top of my own frustrations that my precious iPhone was on the edge of death. At this time I still didn't notice as big of an issue while using the phone (to talk). After many a dropped calls due to this power down issue, I found myself in a quandary between needing to suck it up and buy the iPhone 4 (trying to hold out for the 5). By this time the phone would not stay powered on unless it was plugged in, I had removed all ancillary apps and it still would shut down (it's not software - at least it wasn't any of my apps causing the problem)...to top it off, my youngest was diagnosed with a life threatening food allergy. I NEEDED A PHONE THAT WORKED...I was at an obvious fork in the road, a new iPhone 4 was the way to go, BUT before I succumbed to the purchase I figured my 3GS was trash no matter what so why not at least 'try' to fix it...much to the shagrin of my husband (ye with little faith) I went ahead and ordered the battery. The battery arrived and I asked for some private time away from the kids. If things went well, great! I won't need the 4 and if things went terribly wrong (or the new battery didn't fix the issue...), I had already decided the iPhone 4 purchase would be fine.
The repair went very smoothly...until I was putting everything back together. I encountered a "sinking heart moment" when the camera disconnected from the main board - instructions said specifically NOT to do this. I was able to reattach and get everything aligned correctly and was soon on my way to getting to push the power button.
The best thing I did for this was set up my work space using a plain white piece of paper - easy to find small parts, write on, etc. The #1 thing I would recommend is attaching a piece of scotch tape (or packing tape) to the paper in an inverted fashion so that you can stick the screws to it in the order that they are removed. They're all different sizes, so being able to just stick them on the tape and then grab them when putting them back was genius (if i do say so myself ;)).