Why do my servos make a loud buzzing noise when stationary?

Question: Why do my servos buzz loudly even when not moving?

Answer: A loud buzzing sound from a servo when it’s not moving usually means it’s trying to hold a position under load or receiving a constant signal near its end point. Here’s how to fix it: First, check the servo horn isn’t physically blocked or under mechanical strain. Next, ensure your control signal is stable and correctly centred; noisy or jittery signals cause the servo to constantly adjust and buzz. If using a microcontroller, verify the pulse width modulation (PWM) signal matches the servo’s expected range (usually 1–2 ms pulses). Also, try disconnecting the load to see if the noise stops—if it does, reduce mechanical resistance or use a stronger servo. Finally, check your power supply voltage and current; insufficient power can cause buzzing. Using a dedicated servo power source or adding a capacitor across the power lines often helps. Following these steps should reduce or eliminate the buzzing noise from your servos.