TECHNICAL SUPPORT
Published 2026-03-28
What are you most afraid of when playing withservos? Wrong wiring and burning the equipment, adjusting the neutral point all depends on the fog, not knowing whether theservois fast or slow... these problems can be solved with aservotester. It is like the "medical examiner" of the steering gear, allowing you to easily control the status of the steering gear.
After getting the tester, don't rush to plug in the servo. First, carefully look at the three interfaces. Among them, the signal line is usually yellow or white, the positive electrode is red, and the negative electrode is black or brown. Just plug the servo cable into the "S", "+" and "-" of the tester according to the color. If it is plugged in backwards, the servo will not only not rotate, but may even be burned out.
The tester itself needs to be powered. Generally, a 2S or 3S lithium battery is used. The power supply can be connected through the servo plug or directly connected by welding wire. This step is not too difficult, but before wiring, be sure to confirm that the battery voltage does not exceed the nominal range of the tester.
Calibrating the neutral point is crucial when building a robot or gimbal. First, connect the servo to the tester, and then adjust the knob to the middle position. Under normal circumstances, there will be an indicator light or scale to prompt you. If the angle of the servo arm is not what you expect, don't panic - cut off the power supply first, then manually remove the servo arm, align it with the zero position and then reinstall it.
Some high-end testers have their own fine-tuning function and can fine-tune the pulse width with the help of buttons, thereby achieving accurate calibration within 1 degree. What needs to be kept in mind is that before performing calibration, be sure to confirm that there is no physical damage to the servo itself.
If you want to test how fast the servo rotates, you can switch the tester to manual mode, then slowly turn the knob and carefully observe the time it takes for the servo to rotate from one end of the extreme position to the other end of the extreme position. Taking a common servo as an example, when it rotates from -90 degrees to +90 degrees, a good-performing servo will complete the rotation process in about 0.2 seconds. If the servo rotates obviously slowly or jams, it is likely that the gears are worn or the voltage supply is insufficient. We can use a stopwatch for rough timing, or we can make judgments directly based on the feel of the hand. If the servo rotates too slowly, it is not suitable for use in racing robots. The speeds of servos of different brands vary greatly. After testing, you will have a clearer understanding.
The speed of servos of different brands varies greatly. After completing the test, you will be able to have a more accurate grasp of its speed, and you will have peace of mind. In this way, when using the servos in the future, more reasonable choices can be made based on the test results. For example, for servos whose speed does not meet the requirements, they can be replaced or used in other scenarios that do not require high speed. In this way, the performance of the steering gear can be better exerted and the normal operation and use effect of the related equipment affected by the speed of the steering gear can be avoided.
Some servos will vibrate continuously after being connected to the power supply, or they may not be able to rotate to a specified angle. In this case, the tester is undoubtedly the best "machine inspection tool". Connect the servo in question to the tester separately, switch to automatic reciprocating mode, and let it run for a few minutes. If there are abnormal noises, intermittent jamming, or extreme heat during operation, it can basically be determined that there is a problem with the internal circuit or motor. It is recommended that all newly purchased servos should be run in this way first, so as to avoid discovering problems after installing them on the robot. After all, disassembly and assembly once is too laborious.
When encountering a situation where the tester is not powered on, you must first carefully check whether the battery still has power. Ensuring that the battery power is sufficient is the basis for the normal operation of the device. Then check whether there is any looseness in the wiring part. Loose wiring may lead to poor circuit connection, which may cause the tester to not power on.
If the servo rotates but in the opposite direction, there is no need to rush to change the line at this time. Just flip the "reverse" switch on the tester to easily solve the problem of wrong direction. Occasionally, the servo only vibrates but does not rotate. This may be due to a deviation in the signal frequency output by the tester. The default frequency of most testers is 50Hz, but some digital servos require higher frequencies to work properly. In this case, switching to a model with a frequency adjustment function can solve the problem. In short, these small problems are not complicated to troubleshoot. Don't assume that the steering gear is faulty at the beginning.
The tester usually has three modes: manual mode is suitable for precise angle adjustment. In this mode, the angle can be accurately fine-tuned to meet specific needs; automatic reciprocating mode is suitable for testing durability, through continuous automatic reciprocating operation, to detect the performance of related components under long-term use; neutral point mode is mainly used for quick return to center, which can quickly return the tester to the middle position. When debugging the robotic arm, the manual mode is used to calibrate joint by joint to ensure that each joint can reach a precise position; when doing the car steering test, the automatic mode is used to observe whether the car's steering response is consistent. In addition, some testers with a display can also display the pulse width value in real time, which is of great help for programming parameter adjustment and allows programmers to understand the relevant parameters more intuitively. Flexibly switching between these three modes can save users more than half of their debugging time and improve work efficiency.
Has your servo ever "suspended" or vibrated randomly? How was it resolved later? Welcome to share your troubleshooting experience in the comment area so that more friends can avoid detours.
Update Time：2026-03-28
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