Not in the shop right now, but if I recall correctly, on under the home button on the board there is "s" shaped copper connector sticking up. When you press the home button, it presses this connector down. Use a plastic pry tool and "gently and slightly" pull up on the connector. In other words you want to shape it from "s" to "S", just slightly taller.
What happens is the "S" connector gets pushed down too much towards the logic board and when you press the home button it can't make contact.