I understand your frustration and also see you've been struggling with the problem for quite some time. However, the time it takes to research and tinker on you own is enough for you take it to repair and back. What I want to say is that that Nokia acknowledges the issue, they just denied the accusation regarding the design failure of N900. No matter it's a design failure on N900 or the charger, Nokia has taken the responsibility to repair. I'm not going to stop you from soldering by yourself, but imho the time it takes to research and tinker is enough for you to take your N900 to repair and back. Your choice.