So I turned it off, then turned it back on. This did not help. I turned it back on, went to the website, found the hardware reset procedure and tried it. This did not help either.
Now I have an email off to UA support to see about getting an RMA number. Happily, I still have the original shipping box. I found someone on line who had had a similar problem and whose repair had cost them a couple of hundred dollars. I'm hoping this is no worse than that.
In the meantime, though, the studio is down.