Hello, Received the kit a week ago. Updated the firmware, then connected over bluetooth. Attached the standard and modified servos to the motherboard. From the ARC tried to get the servos work by releasing and trying again changing from 0-100 on vertical servo controller. The four standard servos do not rotate. The modified servos working fine.

On the standard servos. i can hear the motor spinning but the little white part on the top is not spinning.

What is to be done?