I blew up chips on our Motor controllers

if you look at the pins below the heat sink you will see one is missing, that is because it got fried.

I have fried 3 like this so far :(

One was because of bad stepper motors. The steppers also destroyed the internals of 4 other drivers. They have been sent back and replaced. Thank you Dan for getting replacements.

One was my fault, I wired a motor to the drive wrong.

The latest time I don't know why it blew. This is of course the one bothers me the most because the unknowns are preventing us from getting more than 5 motors working in sequence.