An LOL moment, and maybe help for others.
I had thought that the HDMI had gone bad on my Pi. Switching HDMI cables without a reboot didn’t help, so I figured that the Pi was dead.
On a whim, I removed the original cable, and found this: File sharing and storage made simple
So I replaced the cable, with the cable used on my new Pi2, and no change. Then I put the cat chewed cable on the Pi2, and it worked… Until I moved it a bit, then I got the “rainbow under power” icon.
I ssh’d into the original Pi, rebooted and now all is good! It seems that the short in the cable caused the Pi to do strange things, so just replacing the cable without a reboot didn’t help; a reboot was needed.
So now I have a new Pi2 on the way that I already ordered… I think I can find a use for it