arduino code move servo when serial character is recieved via USB to PC

Write a code in arduino to move servo 40 degrees, wait 3 sec and return to 0 degrees. I have a code now but servo keeps vibrating when return to 0 degrees. Arduino UNO GOTECK GS-5515MG Servo 6V external supply for servo This is actual CODE: // Include the Servo library #include <Servo.h> // Declare the Servo pin int servoPin = 3; // Create a servo object Servo Servo1; void setup() { // We need to attach the servo to the used pin number [login to view URL](servoPin); [login to view URL](9600); [login to view URL]("<Listo para recibir datos>"); } char receivedChar; boolean newData = false; void loop() { recvOneChar(); showNewData(); } void recvOneChar() { if ([login to view URL]() > 0) { receivedChar = [login to view URL](); newData = true; } } void showNewData() { if (newData == true) { [login to view URL]("Esta en ... "); [login to view URL](receivedChar); // Make servo go to 50 degrees // Mueve servo a 50 grados [login to view URL](50); delay(1000); [login to view URL](0); newData = false; } }