Due to some improper connected wires to the RoboClaw boards, I have just burned 2 of them. I saw the wires "almost" touching, but it worked in the past, so I said that it should not be a problem. After connecting the battery, the capacitor of the RoboClaw board for the robot leg has made pooc-fssss ... 

The platform electronic was connected to the same USB hub as the one for leg. I do not understand what happens, but also the USB hub and the platform board are not recognized anymore by the PC. I suspect that the short has propagated through USB and affected the USB of the other board.

So, I decided to play safe until things are more advanced. I ordered 2 USB opto isolators which will be connected to each board before entering in the USB hub.