MacFixIt reader Tony reports that Apple is documenting, and fixing problematic front FireWire ports on some Power Mac G5s.
"The folks at the Old Orchard Apple Store replaced the front port panel; they did NOT replace the logic board. I'm glad to say that the video capture dropouts that I was previously experiencing are no longer present in the front FireWire port. Hats off to the OO Apple Store Genii and repair personnel (specifically Shane, Eric, and Ryan). For any G5 users out there who think they may need the same front port panel replaced, let me describe in full the symptoms that I experienced:
"Observed Behavior with GL2 Connected to Front FireWire Port: iMovie video playback exhibited a low frame rate that suggested that frames were being dropped. Audio exhibited a stuttering effect where sound would cut in and out with a rapid frequency on an on-going basis. Occasionally iMovie would display the blue screen and show "Camera Disconnected", but then video playback would continue within a fraction of a second. Importing video fails due to excessive dropped frames or lost connection with camcorder.
"Apple support has a tech article documented internally about a known issue with the front FireWire port on some G5's. The issue has been escalated to the top level engineers."
If you've been having similar problems, you may want to contact Apple for part replacement. Let us know if you are successful.