When my children were growing up I used to tell them that “Experience is a difficult teacher; she gives the test first and the lesson afterwards“. I have found frequently throughout my career that I tend to learn the most when I fail. Mistakes are annoying and often embarrassing, however we tend to learn a lot more from them then we do from success.

I’ve assembled dozens and dozens of HobbyCNC boards. Most without incident. Occasionally a component backwards or missing but generally the product tests out very well. This evening however testing my final board, the A axis motor wasn’t turning. The motor current setting was set at 3 Amps (0.42 volts). I could easily move the stepper motor with my fingers.

By chance, I looked at the microstepping jumpers. I test the boards at 1:2 microstepping (J1 installed). But for the A axis on this board, I forgot to put the jumper on J1. As soon as I added the jumper, the A axis started working perfectly.

I wonder if some of my customers might have had problems getting their axes to start turning and the problem might have been something as simple has no jumpers on the microstepping header!? Thanks to this simple mistake I’ve learned something new that will now go into my debugging FAQs!