Review on Unleash Your Arduino Creativity with the Longruner Arduino Professional Mechanical LKB02 by Adam Tidd

Mine must have come out of the bin! ENGINES: First let me say that the engines themselves seem fine so far. CNC SHIELD: The board had green corrosion on all the brass pins, making connecting/disconnecting jumpers, drivers, and motors more difficult than it should be (not to mention poor electrical contact). The external power connector (the blue part with the screws) had a white film of corrosion on the top of the screws, and the metal case inside was covered in rust. The Z-axis capacitor also has corrosion at the solder joint. DRV8825 DRIVERS: I've spent the last few days trying every possible configuration to get the drivers to drive the motors properly. Of the 4 driver boards, 1 has a different configuration, meaning it needs a different Vref setting for current limit, just like the other 3. This caused the motor connected to the driver to shake (motors worked fine when they connected to other drivers). ) on each axis to which the driver has been connected. Okay, that's easy enough to fix. Just discard the instructions in the item listing and read the datasheet to find out the appropriate Vref needed for the current you want. If that was the only problem I could live with it as long as I could figure it out before all the engines burned out. EVEN the other driver only moves in one direction. Run it through each axle/motor combination again to rule out the board and motor as part of the problem. It turns out that on this driver board, the DIR pin is shorted to GND (resistance 0, not the level of the internal pull-up resistor). I haven't gotten to the limit switches and brackets yet. The buyer doesn't need to deal with the quality control.