I am using arduino servo library and I was able to make two servos work perfectly, now no matter what I do, they both exhibit the same behavior, i.e. When powered off I turn the arm all the way clockwise then when I power it on and connect to PWM, it turns all the way CCW, stops and then keeps buzzing as if the motor is still running but the arm has been stopped by the mechanical stops.
I've tried using write.microSeconds(500), 1000, 1500, 2000, 2500. For all cases, I get the same behavior. I connected an LED to the attached pin (without servo) and it's dim for the 500u case and gets brighter in steps as I step up the pulse width.
One servo is an sg90 the other is a HiTec HS-322HD. Both show the same behavior and both were working before. Both are supposed to go to the neutral position with a pulse width of 1500uS.
I've tried powering the sg90 from the arduino supply and I get the same thing. I have not tried the HiTec on Arduino supply, I'm afraid it might draw too much current. It runs on a 5v ac-dc adapter that I hacked by splicing in two wires to connect to my breadboard.
I've tried attaching to pins 8,9,10, and 11. All show the same behavior.
I have not opened up either servo. I have not tried to convert them to Continuous Rotation Servos.
Any help would be appreciated. I am stuck!