Hi, I have recently acquired a second hand powerbook, when I got it no airport networks can be seen on the drop down menu.

I checked the airport antenna cable and it was damaged so to save any hassle I have replaced the whole antenna unit with a brand new one, I have also double checked the airport card itself with another one I know works. The mac sees the card, but still cannot see any networks! I have got access to several and all appear on another powerbook.