Just wondering, have you started it from another system in Target Disk Mode and tried using the Airport like that? That would tell you for certain if it was hardware or software related.

I had this same computer a while back and it got pretty terrible airport reception -- it would regularly not find networks that a G4 iBook would find. To troubleshoot, I'd test it by bringing it right next to a working wifi transmitter to see if it picks up the signal.

Just as something else to try, I'd make sure no one got the antenna wires mixed up. One is for the Airport and the other is for Bluetooth.

This is probably obvious, and it sounds like you know what you're doing, but make sure the connector is firmly plugged into the airport. Sometimes it feel like it's attached, but then if you apply more pressure you get another "click" when it goes all the way in, and that definitely affects reception. Other than that, if you're trying a known-good card, I'm not sure what would be the problem, because you've replaced all the hardware. Have you done a fresh install of the OS? I've seen machines with gunked-up VPN settings that had wireless problems until the network config was reset. Also, I've seen machines with 10.5.0, i.e. machines that were not patched to the latest OS revision that could not see the wireless card or otherwise had odd wireless issues.

just read your last post about the PB not going to sleep and I had this ultra-obvious idea I don't think anybody has suggested here yet, not sure if you have already tried....

have you tried resetting both the PRAM and the PMU?

just a thought. the reed switch would be input to the PMU to control sleep, perhaps reed switch is ok but PMU and/or the PRAM is in some weird state that somehow is affecting sleep and AirPort functions??

maybe crazy idea, but if you haven't done so already give it a try

Hi, when i replaced the airport antenna I also put in a new hard drive which I installed 10.4.1 on to so I doubt this would be the problem. Is there anyway it could be a problem where the airport card meets the logicboard? If so any ideas how I could fix it?

Have tried all the things above but still no networks showing, I have replaced the airport antenna inside the mac with a new unit, I have checked the airport card by swapping it with one I know definately works on another machine. I have wiped and re-instaleld the OS and checked for any damage ie bent pins in the card slot.. and STILL get no networks showing, the mac sees the card no problem but just cannot see any networks!!! HELP!!

The trouble with those usb sticks is they are prone to snapping and breaking which is why I really need the internal one to do it's job.

The other airport card that I tried definately works (see original post) it is currently in my other laptop talking to all the networks in the house and a work a treat so I know there are no issues with either card as I have tried them in the laptop that does work and they both see all networks fine.

Here's another thought, I have just noticed that when the lid is closed the mac wont go to sleep, could this be related? I presume that this is a faulty reed switch but dont know if it would affect the networks not showing up in the airport control panel

Tried both of these and it made no difference at all