I use a multimeter to measure the output voltage of motor 1 and motor 2. On motor 1 voltage output was 6.50v and for motor 2 output voltage was 8.10v
I thought that my motor shield may be broken, but when I test it on arduino with the same code, output voltage was approximately 6.60v in both motors
Is the motor shield not compatible with Arduino mega?
Or is it a bug of AFMotor library?
I have the same problem with the mega . It was working on top of an UNO R3 Saint Smart and then I got an Original Arduino MEGA and the motor goes fine when in backward mode but the RIGHT one does not move or move really slow. It happens the same with every mega I tried.
Then try to connect the motors to M3 and M4 terminals @ 64khz instead of M1/M2
Ps: I think that Adafruit says that M3/M4 do not support 64khz, but I have not problem when I used this setting