hi, i know its a bit old post but this forum helped me out and i want to share my solution that really works.

the wifi problem seems to be a connection problem between some electronic parts as it works when u hit . so i opened my pocket pc(no need to worry only four screws holding it).and replaced a thick paper just over the biggest metal part which lays at the upper part of the motherboard.(this metal part has small black sponges glued to it).the thickness must just enough to apply mild pressure on the chip (or whatever).and without moving the paper screwed the case back thats all and my ipaq works flawless

though its a bit old device ones who have put it somewhere may fix it and use it again,hope the solution will work for u