Are you using flux when you solder ?
If you aren't, that's why the connection is breaking loose. The solder is making a cold joint. Use a little flux paste on the tip of the wire, get a dab of solder on your iron tip, place the wire on the connection and touch the wire just above end (dont touch teh ps2 board with it. The flux will make the solder flow.
If you are using flux, and you know how to solder, I apologize for insulting your intelegence.
