Howard Nurse, W6HN
After looking at the 7610 capabilities in RigPi Advanced Radio settings, I see that power off/on is not currently supported by Hamlib. I'm surprised, but it is a feature I hope they will add.
Once you initialize the Keyer it will be happy. It also works with a paddle even though you aren't using a radio. (That's one thing the speed pot is for.)
I've owned two SB-200's through the years, nice amp!