Replacing my dying iPhone 3gs battery--daunting, but doable
20 - 30 minuten
My 3gs battery would totally fail at about the 50% charge, and if I was using anything that accessed a network (3g or wireless), my charge would quickly run down to zero, sometimes after less than a minute of network activity. After looking through various forums, battery replacement seemed the way to go.
I had great plans to have everything neatly spread out on our large kitchen table for this repair. Instead, due to delays getting to it and general impatience, I did the repair on my crowded computer work desk. I did use an ice cube tray to keep the screws sorted (a good idea that I almost sabotaged by not differentiating between the partially threaded and fully threaded screws holding down the motherboard--fortunately I was able to rectify this by pulling out my handy magnifying glass and properly identifying the screws in question). Once the battery was replaced, the "do it all in reverse" instruction proved easier said than done. The round connectors were difficult to snap back together (connectors 6 & 7, I believe), and getting the upper ribbon (#3) properly seated under the white clip so it wouldn't pull back out took several attempts. I couldn't get the case to close again until after several attempts to re-seat the camera & motherboard--finally firm pressure and an audible click did the trick. I'm estimating the whole process took about an hour and a half. (Remember, I had to re-sort the screws!)
The iFixit instructions were very good. I also found HighT3chDad's video on YouTube to be extremely helpful. He gave some valuable heads-up tips (beware the round snap connectors, reconnecting ribbon three, the camera clip, and a very detailed reconstruction narration, with pitfalls noted). Reseating the camera took some extra wiggling and positioning, and it took more pressure than I was initially willing to give to get everything completely seated before putting the case back together. I had already taken apart my old 12" Powerbook G4 to upgrade the hard drive, and this was much more difficult due to the extremely constricted amount of space. (Although there were definitely fewer screws to worry about on the iPhone.) Not for the faint-hearted, but with all the excellent instructions and how-tos available online, it can be done!