Review on Unleash Your Arduino Creativity with the Longruner Arduino Professional Mechanical LKB02 by Elijah Balzarini

I am an electrical engineer by training and design electronics for manufacturing every day. I have this experiment kit and god I have the experiment. I read the instructions, downloaded the firmware zip file - compiled and tested. The Arduino spoke great to GRBL. I connected the shield, a motor and a motor as the instructions say. When I started sending the G-code, the motor ran fine. I switched off the power and tested each motor with the same driver. I started draining where the motor wouldn't stop and the ammeter on my PSU was going crazy - and I was being conservative as the PSU was keeping it at 11.5V so I checked the heatsink on the driver and it was getting very hot so I tried adjusting the trim for VREF and no improvement. I turned off the power, plugged in another driver and similar behavior - everything started fine but started to heat up and misbehave as expected. Didn't have time to play around with it. Came back to this tonight about two weeks later and started on another motor and motor driver. This time the driver exploded before I even sent the G-code - a brief trail of flame and some gray smoke. Turn everything off and the Arduino seems to be behaving strangely. Open the GRBL firmware project in Arduino and the Arduino doesn't accept it. Grab another UNO from my drawer and it loads with no problem, so I know it's not a settings issue - it blew up. Reconnect the candle to the old one and check if at boot the prints in the console differ from those of the other Arduino - that's why it doesn't accept flashing and the flash is corrupted. Try the shield with my other Arduino and the new motor driver. The motors don't turn. Try all three engines. Nothing. Pull out another CNC I own and plug in motors - they all work. So the shield blew, the Arduino blew, and at least two of the motor drivers blew - the question is if they ever worked. I followed directions to T to check and he sent me a smoke signal that literally said "We're out of business".