TECHNICAL SUPPORT
Published 2026-03-09
Have you also encountered this situation? I was full of joy when I bought aservoand wanted to install it on the robot or model I made. As a result, when I put it on, it was as fierce as a tiger. It would not move at all, or it would shake like a sieve. Actually, nine times out of ten, it's not that theservoitself is broken, but that you didn't give it a comprehensive "physical examination" before getting on the plane. Today we are going to talk about how to easily master theservotesting method by watching videos, so that you can have a good idea before installing the machine.
When you get a new servo, don’t rush to connect it to the power supply first. We can first hold the servo in our hands and turn its output shaft. If it feels jerky or even stuck, there may be an issue with the internal gears. Then gently shake the connection between the rocker arm and the servo housing. If the frame feels large, the virtual position of the servo may be more obvious, and the accuracy of installation on the equipment will be affected. This step is like doing a physical inspection of the servo to eliminate flaws that can be seen at a glance.
️Then the last step before turning on the power is to check the wiring sequence of the servo. For different brands of servos, the color arrangement of signal wires, power wires and ground wires may be different. A common one is usually a red (orange) letter on a brown ground, while a JR may be a red (white) letter on a black ground. Be sure to check clearly. If the power cord and signal cord are connected reversely, it may burn the servo at worst, or take away your control board with it. This step requires a lot of energy.
When it comes to testing servos, the simplest and most direct tool is a servo tester. This thing costs tens of dollars apiece and is extremely stupid to operate. Plug in the servo, set it to test mode, and then turn the potentiometer knob above. You will find that as you turn the knob, the servo's rocker arm will accurately rotate to the corresponding angle. At this time, you can observe whether the position of the rocker arm stops accurately every time from 0 degrees to 45 degrees, and then to 90 degrees, and whether there is any shaking back and forth.
1. In addition to manual mode, many testers also have automatic mode. After turning on the automatic mode, the servo will swing back and forth between 0 degrees and 180 degrees (or the set limit angle). You can stand nearby and carefully observe its movement. Listen for any abnormal "buzzing" sounds, see if the swing is crisp and clear when reaching the extreme positions at both ends, and see if there is any squealing due to overload. If everything is smooth and quiet, then there will be no big problems with this servo in terms of basic movement functions.
What should I do if I don’t have a servo tester on hand? Don't worry, you can test it with your remote control and receiver. Plug the servo into any channel of the receiver, such as channel 1 (usually controls direction). Turn on the remote control and receiver, and then push the corresponding rocker or knob on the remote control. At this time, the servo rocker arm will follow your operation. This method can not only test the steering gear, but also check whether your remote control and receiver are working properly.
You can try pushing the joystick at a very slow speed to feel the linearity of the servo rotation. With a good servo, its rotation speed will perfectly match the speed at which you push the joystick, making it very smooth. If you feel that the servo rotates intermittently, or the speed is suddenly fast and slow, then the potentiometer or control circuit inside the servo may be defective. This problem may not be obvious when it is unloaded, but once it is loaded, it will seriously affect the controllability of the equipment.
The neutral point of the servo is a key indicator, especially when installing a robot servo or an aircraft control surface. Plug in the servo and don't give it any signal. In theory, the rocker arm should automatically return to its mechanical center point. But you can send it a standard 1.5ms pulse width signal (the neutral point of most remote controls and testers is this value), and then see if the rocker arm is exactly parallel to the servo housing, or aligned at the 0-degree position you want. If it is not accurate, subsequent installation and debugging will be very troublesome.
If you find that the neutral point is off, don't jump to conclusions yet. You can change the receiver channel or try another tester. If there is still a deviation, it means that the accuracy of the steering gear itself is not very high. For a less demanding model, such as a large truck, this deviation may not matter. But if it is used on a camera gimbal or bionic robot, this slight deviation will be magnified many times in the final effect. At this time, you have to consider changing to a higher-precision servo.
If you want to know how powerful the servo is, just looking at the numbers on the parameter table is not enough. We can use a simple native method. Fix the servo, tie a rope to the rocker arm, and hang a spring scale on the other end of the rope. Then give the steering gear a rotation signal and ask it to pull the spring scale. At the moment it fails to pull, you can roughly estimate its torque by looking at the reading on the spring scale. Of course, this method is not very accurate, but it is already of great reference value for us to compare the power of different servos.
Measuring speed is more intuitive. Turn on the automatic mode of the servo tester and let it swing between the two extreme angles at full speed. You can turn on the slow-motion shooting function on your phone and record the process. Then play it back and count how many frames it takes to swing from side to side. Because you know the slow-motion frame rate of your phone, you can calculate the time it takes for it to swing at this angle. Compare it with the manufacturer's nominal value, such as "0.12 seconds/60 degrees", and you will know whether there are virtual standard parameters.
There are so many learning resources on the Internet now. Instead of thinking about it by yourself, it is better to search for some videos on servo evaluation or test methods. On station B or online, you can find many detailed videos made by experts by searching with keywords such as "servo test", "servo selection", and "XX brand servo unboxing". They will use various professional equipment, such as digital oscilloscopes to measure signals, or torque meters to measure torque. Watching them operate is a hundred times more intuitive than reading the instructions yourself.
When watching the video, pay more attention to the details of their tests. For example, they will take apart the servo and show you whether the gears inside are made of plastic or metal, and how big the motor is. They will also simulate the situation where the servo is blocked and listen to how loud the noise is. Watch a few more of these videos, and you will have a very specific impression of what kind of servo is a good servo. If you buy a servo in the future, you can avoid many pitfalls and directly choose the one that best suits your project.
Okay, let’s stop talking about how to test the servo before putting it on the aircraft. I wonder if you have ever encountered any particularly weird malfunctions while playing with the servo? Or do you have your own unique testing tips? Welcome to leave a message and share in the comment area. Let’s communicate and make progress together. If you find it useful, don’t forget to give it a like and share it with friends around you who also love to do things!
Update Time：2026-03-09
Contact Kpower's product specialist to recommend suitable motor or gearbox for your product.
