Bizarre iSight problem.

Hi. I have a final revision 17" PowerBook G4 and an external iSight. The iSight hasn't worked on my computer for ages; it stopped working when I upgraded to 10.4.8. The computer doesn't recognize it. The green light goes on for a second and it shuts off. Applications say that either a camera is not connected and it doesn't show up in system profiler.

Just yesterday, I finally got around to doing a full system erase and install. Completely wiped my HD and started from scratch. The iSight still doesn't work.

So of course you would think it would be hardware failure with the iSight itself, right? But on my mom's iMac G4, it works like brand new. The iMac is running 10.4.8, the same update that caused my PowerBook to stop recognizing the iSight. Used the same cable to test it too.

How can it be that a fully working iSight doesn't work on my PowerBook with a completely clean install of OS X, with the iSight extension properly in place and everything, and with a working Firewire port? It makes no sense.

Any suggestions?

Guesses?

Speculation?

 

In my previous post I was unable to think of any Firewire devices I could perform a test with, however, I remembered about a Compact Flash reader that happened to use Firewire. I brought it over to my PowerBook, and it failed to mount a CF card that mounted fine on the iMac.

The port may well have failed.

Is there any definitive way to verify that the port isn't working, or is my only option to confirm that various devices do not work with it?