Yes, it sounds like a hardware failure of some kind. Although I haven't heard this particular symptom described before, similar kinds of symptoms were caused by failures in the circuitry embedded within the VFD glass.

There is a chance it might be something you can fix yourself, though. Have a peek at the two troubleshooting guides here and here, and see if the fuses or the display ribbon cable are the culprit. Otherwise, it's probably a Stu or Rob Job.