I have seen them blow the transistors for 1 direction, theres a guy in Aus thats gone through 2-3 tanks (1 tiger, 2 T34's) for this exact reason (lost drive to one direction, like left side reverse) so its gotta be a fault... usually by having less features (1 speed) you get less trouble, the original WSN (non-ir) boards were fairly tough, the newer ones are much cheaper made.