There is a Bug in Version 1.8.10 of the Arduino IDE using analogWrite() for PWM on Arduino Mega 2560. If i use analogWrite() with any value for the pwm-Pins once in the loop()-Method everything works fine. If I put a second call of analogWrite() with the same pin and any value that is not 0 or 255, nothing happens. The loop-Method keeps on working, but the PWM-Pin used in analogWrite() shows an continous output of 0V. In Version 1.8.9 the same programm works fine.