zoomkat:
Did they smoke when you connected them to the 9v?
I only had them plugged in for a few seconds -- I unplugged them as soon as I saw what was going on -- so no, if they were going to start smoking i didn't give them a chance. However, now that you bring it up, just one of the servos was not smoking but very hot to the touch when it was connected to the Arduino power and active for a few minutes. That particular servo was acting a bit funny and getting stuck in places; it might just be defective.
I doubt it's an overdrive problem, because I heard that one can power a 9g servo with a 9v no problem. I suppose that could be wrong, but it doesn't seem like that would produce the symptoms I'm experienceing. ...would it?