What can make the button pin break and burn the solder like that?
Another thing, usually the power button is righ after the AC cord, in this case the TV's power supply has several components between the cord and the button, several, capacitors resistors, diodes and a transformer. It looks as if the TV has a mini power supply inside its power supply.
Could it be that the TV itself converts 220v into 110v before the power button? (220v to 110v its just a thought)