[Elecraft] Turn on KAT500?

[Dave Fugleberg]

Still trying to sort out my transverter problem - see my first post on that
today. I have only the transverters connected to the K3. When I connect
power to the rig runner, the k3 tried to power on by itself and displays
'turn on KAT 500'. I don't even have one, but I do have a P3, which is not
connected at this point.
I vaguely recall seeing that message when I first got my P3, and finding a
solution, I don't remember what it was.
Help?!