The gearbox SPG7950A-45 is composed by a servo and a pipe mount. The servo is HS 7950TH a motor with high torque. The version mounted on the gearbox is a modified unofficial version. If you want to make a self-repair in case of damage, the modification void your warranty. The servo is not expensive and often is cheaper a self substitution, than resending to factory.
If you use properly it is really difficult to completely damage the servo. Gears can wear out after a long usage but you can buy a replacement kit and you don’t have to replace the whole servo motor.
You can find spare parts in this site.
In this modified version a feedback potentiometer have been connected to the servo box.
The potentiometer is used to precisely control the rotation of the main gear and of the main axis of the gearbox.
180° gearbox with Arduino
The servomotor are controlled by an impulse between 900 and 2000 us. Every microcontroller that can provide such signal can be used to control our box.
The cable of the box has 3 wires. Yellow, red, black. The red and black are used for power supply red: (+), black (-). The yellow wire is used for signal.