Hi all,
I have been stumped by this strange problem where my Arduino Mega 2560 (brand new)'s analogWrite pins wouldn't work. I am trying to power 5V Logic input for my 3 motor drivers (VNH2SP30 Motor Driver Carrier MD01B) with PWM pins 5, 6, and 7. However, whenever I upload my program to my Arduino, the analogWrite for pin 6 would only output 5V, whereas pins 6 and 7 would output 0.14mV. Whenever I try different pins (for instance, pins 2, 3, and 4), at least one of the pins wouldn't work with an output of 0.14mV. I have tried on 3 separate different types of computers, but the results are all the same.
This may not be relevant, but whenever I add an additional analogWrite(7, 250); after the analogWrite(7, 250);, my pins would all work fine. If I add random delay(5);s here and there, pin 6 would stop working and pin 5 would start working for some reason.
Is my new Arduino Mega 2560 broken? Is the Arduino IDE software bugged due to the new 1.8.12 update? Any ideas?
Thanks in advance! 
Here is my program:
void setup() {
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(22,OUTPUT);
pinMode(23,OUTPUT);
pinMode(24,OUTPUT);
pinMode(25,OUTPUT);
pinMode(26,OUTPUT);
pinMode(27,OUTPUT);
}
void loop() {
analogWrite(5, 255);
analogWrite(6, 255);
analogWrite(7, 255);
digitalWrite(22, HIGH);
digitalWrite(23, LOW);
digitalWrite(24, HIGH);
digitalWrite(25, LOW);
digitalWrite(26, HIGH);
digitalWrite(27, LOW);
}