#include <Servo.h>
Servo serv1;

void setup() {
  serv1.attach(3); // Pin 3
}

void loop() {
  serv1.write(90); // No response
  delay(3000);

  serv1.writeMicroseconds(1472); // Works
  delay(3000);

  serv1.write(0); // No response
  delay(3000);

  serv1.writeMicroseconds(1800); // Works
  delay(3000);
}