It's really not that hard. Take off the two covers in the back, remove the screws holding the hard drive and DVD drive in place and remove both. Then you have to take out just about every screw in order to separate the two halves of the case. But there's no soldering involved. When you had the keyboard off, the AC connection is visable through the hole that's about six inches in from the right side. It's the top connection, use something flat and plastic and screwdriver shaped to wiggle the male and female parts apart. You should see four pins visible on the part that's connected to the motherboard. Unfortunately you're going to have to remove the back to get the palm rest/ touch pad half of the case out of the way. But once you do, the AC adapter just slides right out and the new one slides right into it's place. Here's a pretty good tutorial on what you need to do:http://www.irisvista.com/tech/laptops/Toshiba-Satellite-L505-L505D/remove-laptop-motherboard-1.htm
Sorry if my answer is rambling, I'm running on not very much sleep.
feel free to email me smattnc at gee mail dot com if you have furthur questions, I've taken apart this particular model laptop over and over... I have spare parts if you need as well.