Sorry, I don't have any of these servos, I mainly have AX servos and now a few XL and XM. So maybe someone from Robotis might be able to figure something out, but.
My guess is, it would help to have some additional information, like what is not working?
is do you have it hooked up to some controller? Which one, controlled
by ??? You are trying to get it to do??? What is it actually doing?
According to your video(qq视频20180416170104.mp4), it seems the motor is not in a good condition.
Or check if the power supply is providing enough current and cable is fine.
You might need to repair the motor
The second video with Dynamixel Wizard, if you set both CW/CCW Limit to '0', Dynamixel will operate as Wheel Mode.
Wheel mode doesn't accept position command therefore you cannot control the angle. If you wish to control the angle, you have to set as Joint Mode
Please see the eManual. Click on the "Google" button to see language translation option
If the Dynamixel in the second video is the identical Dynamixel with the first video, you need to repair the motor as it shows Overload Error in bit 5 after sending an instruction.
This seems to be either the motor core draws too much current due to a malfunction or the damaged gear.