I checked the optos and the potentiometer circuit and works correct. I can't find no short circuit on the motherboard or the TB6600.

My hypothesis is that the problem is in the tb6600, because the other part of the circuit is simple and seems to work correct. However I'm surprised that when I switch on the board, the "internal mosfet" seems to work. As explained bobgrant, one phase work and the other no. And they changed.

I will continue testing.

Thanks for the help and sorry for my english!