i had the same problem (no sound through the right ear)
i followed the repair guide, teared it apart and then, when i had the jack out of it i used a flashlight and a soldering iron
use a very thin soldering iron, make it really hot, put very much solder on it
then stick it in the jack you have to be VERY FAST!!! otherwise the plastic will melt
now you have solder on the contacts and they touch the headphone plug again :)
worked fine for me, but only do this when you know how to solder!
it's a little risky but it's worth it