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

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

Answer: Loud buzzing from servos at rest usually means they're constantly receiving a PWM signal asking them to hold a position under load. This causes the motor to strain and vibrate. First, check your servo signal: ensure the control signal is steady and matches the servo's neutral or desired position. If the signal is jittery or off-centre, the servo will try to correct itself continuously, causing noise.

Second, examine the mechanical setup. If the servo horn or linkage is binding or under mechanical stress, the servo motor will work harder to maintain position, leading to buzzing. Try disconnecting the linkage and see if the noise stops.

Third, consider your power supply. Insufficient or noisy power can cause servo jitter and buzzing. Use a stable 5–6V supply capable of delivering enough current.

Finally, if the servo is old or damaged, internal wear might cause buzzing. Testing with a new servo can help diagnose this.

In summary: verify signal quality, reduce mechanical load, ensure proper power, and test hardware condition to stop servo buzzing.