PowerMac G4 Firewire Bus Has Died

I was just doing a backup to a Firewire drive on my old G4 Mac, which went fine. Unplugged the drive & plugged another drive in - nothing! The drives are fine. Looks like the bus has died all of a sudden. This seems a bit strange as I have never heard of a Firewire bus dying before. Anyone have an old Firewire PCI card sitting around by any chance?

Richard, have you tried the usual first responses with the old girl:
Safe Boot & Restart
Reset PRAM

Hi @JimWOz. No I haven’t yet. Will try that this afternoon & reset PMU if that doesn’t work. Thanks for the reply.