TECHNICAL SUPPORT
Published 2026-03-03
Hey, you were tinkering with the steering gear, and did you suddenly find that it didn't obey your orders? For example, it keeps shaking, or can't turn to the designated position? It is very possible that there is something wrong with the potentiometer in theservo. Although this thing is small, it is the "sensory organ" of the steering gear. Once it breaks down, the entire steering gear's work will be disrupted. Now let me talk to you about what will happen if this little potentiometer strikes.
The main job of the potentiometer inside the steering gear is to report "where am I turning now" to the control board at all times. Once it breaks down, the most direct feeling is that theservostarts to "drizzle". You may see it shaking in small increments on its own, like a chill, without you giving it any instructions. Or when rotating, the movement becomes choppy and extremely unsmooth.
In addition to jitter, the more obvious symptom is a complete failure of position control. If you ask it to turn to 90 degrees, it may only turn to 45 degrees and then stop, or it may overshoot and go to 180 degrees. This is because the position feedback signal received by the control board is wrong. It thinks that theservohas not reached the position and keeps turning, resulting in a deviation.
Ninety-nine times the reason why the servo spins around like "crazy" is because the feedback signal is broken or messed up. You can think of the entire steering gear control system as a closed feedback loop. The control chip issues instructions and the motor starts to rotate. At the same time, the potentiometer monitors the rotation angle in real time and transmits the data back. Once this feedback loop is disconnected, the control chip becomes "blind".
When the potentiometer is worn or has poor internal contact, the data it transmits to the chip will be messy. For example, the servo has obviously turned to the extreme position of 180 degrees, but the data sent from the potentiometer to the chip shows that it has only turned to 90 degrees. When the chip receives this error message, it will continue to command the motor to "refuel and rotate." The result is that the servo is desperately trying to break through the physical limit and makes a "click-click" sound, which is very scary.
If it is confirmed that the potentiometer is broken, friends with strong hands-on ability can theoretically replace it by themselves. You first have to disassemble the back cover of the servo and find the small potentiometer connected to the output shaft. Usually it is a small blue component with three legs. Use a multimeter to measure it. If the resistance change is not linear or infinite, then it is basically sentenced to death.
But I have to pour cold water on you. It’s actually quite a hassle to change this yourself.️First, you have to buy a potentiometer with a completely matching model. This thing cannot be used just by picking one up. The resistance range and size must be consistent.️Second, desoldering and welding work requires a bit of skill. If you shake your hand, the circuit next to it may become useless.️Third, and most importantly, you need to re-calibrate the zero point after replacement, otherwise the position will still be inaccurate. Therefore, for ordinary players, it may be more worry-free to just replace the servo with a new one.
Not all servos are completely ruined once they break down. We have to give it a "physical examination" first. You can first gently turn the output arm of the servo with your hand to feel whether the gear engagement is smooth and whether there is any stuck or loose feeling. Then, power it on, pinch the output arm with your hand and feel it to see if it is strong and can stop steadily at the command position.
If only the potentiometer is broken, the motor and gearbox of the servo are actually still good. When the power is turned on, you can feel that it has the power to rotate, but it just rotates randomly due to wrong feedback. This situation is considered "semi-disabled" and has salvage value. But if there is no response at all after power is turned on, or the gear makes a "clicking" noise and slips when turning, it is probably because the motor is burned or the teeth of the gearbox are knocked out, and then it can really be declared that it has reached the end of its life.
Speaking of prevention, in fact, many steering gear potentiometers are damaged due to mechanical wear. When the servo is working, especially when it rotates back and forth frequently, the carbon diaphragm inside the potentiometer will be constantly scratched by the brush, and will naturally wear out over time. Therefore, when choosing a servo, if it is used in a scene that requires continuous swinging for a long time, you can consider the model with metal gears and high-quality potentiometers.
In addition, it is also important to maintain the "physical health" of the steering gear. Try to avoid leaving the servo in the extreme position for a long time, because this will not only cause high current, but also put the greatest pressure on the potentiometer. If conditions permit, you can regularly add some grease to the gears of the steering gear to reduce the resistance of the entire transmission system. A small physical limit stop can also prevent the servo from over-rotating due to program errors and protect the potentiometer from the root.
This is indeed a critical issue. If the model is wrong, all efforts will be in vain. The safest way is to disassemble your broken servo and look directly at the silk screen on the potentiometer. Usually there is a resistance value marked on it, such as "5K" or "10K", and this parameter must be consistent. At the same time, pay attention to the fact that it has a positioning slot, and the mechanical installation dimensions must be exactly the same as the original one.
If you can't read the silk screen or can't buy the original model, then you have to search the Internet with the broken potentiometer, or consult the technical support of the steering gear manufacturer. It is also a good idea to search the company's official website. Many professional manufacturers will provide detailed accessory information. Remember, this is a precision feedback component. Don’t be greedy for cheap and buy products from unknown sources. Otherwise, the new one will break after a few days of use, which means the gain outweighs the loss.
After talking so much, I wonder which brand of steering gear you are using? Have you ever encountered similar headaches? Welcome to leave a message in the comment area, let's communicate together, and don't forget to like and share so that more friends who play servos can see this article.
Update Time：2026-03-03
Contact Kpower's product specialist to recommend suitable motor or gearbox for your product.
