[X4U] FireWire quits working

[John Erdman]

I've got a G4-AGP and a year old iMac G5 in front of me. Both have OS  
10.4.7

  I use a 120 GB Hard drive in a Firewire enclosure with an Oxford  
bridge.  For some unknown reason the iMac has stopped recognizing  
that drive but the G4 sees it fine. (It's only connected to one  
computer at a time).

When I run the system profiler on the G4 and look at the FW info with  
nothing connected it shows a message that it can handle up to 400 Mb/ 
sec. With the HD plugged in all the relevant drive info is there.

But on the iMac in the Profiler window under the FW info... it shows  
nothing not even the message that it can handle up to 400/800 Mb/sec.


And further I tried starting up the iMac in target mode. The screen  
looks like it does so successfully and the internal fan resup.... but  
when I connect the G4 nothing shows up.

It appears that the iMac has lost the FW bus.. Is this posssible? or  
a likely diagnosis?

Any suggestions for confirming the problem or trouble shooting it?

Thanks,
John