[FW] iSight Cam, iPod and Firewire Drives

[Johns Maillist]

The problems between having the iSight camera and the iPod plugged in 
at the same time, I believe, is well known.
I now find some interesting behavior, that I am just not sure how to 
explain. I was starting to believe it is the iSight, but now think a 
firewire bus is the issue.
First, running a G4, 1.25, 2 GB Ram, OS X 10.3.7. External Dual 
Firewire (Oxford 911 updated chip) with 150 and 80 GB drives.
I noticed that every so often (I don;t remember the iSight status at 
the time) I would get the Device Removed message on screen and my 
external drives were gone.
Now, the external drives will not even run, and the power lights 
flicker, and the drives click, when turned on.
I now have noticed (guess with the FW drives offline, the system is 
quieter), that the system seems to drag down (fan slows down) when the 
iSight is plugged in. When I unplug it, the speed returns.
Any ideas, or is there a diagnostics section I can use to see if it is 
a problem with the bus?
Also, is it possible that a powered firewire hub would help?
TIA,
John