I recently purchased a transmitter+receiver and PPM encoder for the Pi0 drone I've been building. I was able to connect everything and start the calibration mode. I can control the motors via RC now.
However, I'm still having the same issue with one of the four motors - it doesn't spin initially when the drone is armed. I've been having this issue from the beginning and thought properly calibrating the ESCs via the RC would fix the problem. I've noticed that the fourth motor does spin up once the throttle goes above ~40%. But at the default arming and low throttle speeds the fourth motor does not spin.
Do I need to actually perform any specific procedures to calibrate the motors when in calibration mode? Or is that done automatically once the RC + receiver + PPM are paired? Do you think I need to buy a new ESC?