In January 2015 I bought (9) TS900 servos from Hobby King.
I am building a 30cc gas 3D plane and thought for the money the servos sound so good with there specification.
5 of these servos do not work as they should right out of the box
I have a switching 6v sbec for power. I tested all servos to 6v. 4 of them jitter badly, one stops till you move the servo arm.
It is NOT hobby king but the manufacture of the servos that has let the product come to the public past quality control in this mess.
I am in the process of getting credit from the servos from hobby king.
This has been my experience with track star thus far. The servos I have left work grate, but I hope they don't fail. I will not buy a track star product again.