Ok so I tried turning off failsafe . . .
so when I do, it no longer holds it's position when powered (good)
but it also no longer accepts a RC signal to rotate! (bad)
I emailed Hitec my original question, and got this reply:
Those two servos are designed for rc use. This feature, holding position
after losing signal, is how they are designed. There is no way to turn it
off. You can only prevent that by shutting down the power going to them.
The HSR-5995 is for robotics, so it doesn't have this feature.
I replied back with this question:
Where might I find this information in the datasheet so that I do not
make this mistake again?
I'll let you guys know if they reply . . .