Stpper driver outputting 12V not 5V? CNC controller

Hi All!

I hope you are well,

I had a quick question about using the Sparkfun Easy driver. I created a PCB (CNC controller for stepper drivers) for my current project and discovered that one of the easy drivers does not work rotate the servo motor:

The driver without the heatsink works (the RED LED turns on and all pins have the same voltage as the other working easy driver)

The header pins are where I connect the NEMA 17 steppers.

I have tried:

  • Replacing the Easy driver as I deemed it was faulty due to the strange 12V output.
  • Just running the stepper driver by itself, still doesn't work.
  • swapping over the input motors to make sure it wasn't the motors that were faulty.
  • Measured the working driver's voltages for all pins and discovered that all pins have the same voltage except the output, as explained in the picture, a normal driver should pulse 5V to the stepper. Here I'm getting 12v for 2 pins and nothing for the other pins (got the same output when I replaced the easy driver).

I will try:

  • A new PCB as there may be a scratch with this board.

The input is through an adjustable power supply so I can monitor and control the input voltage. Nothing strange about how much current it is drawing - it's as if it's 'working'.

See below for the schematic for this PCB, as this may come in handy. The idea is that the user plugs in one power supply and it dishes out 12V for the steppers and 5V to run the rest of the circuit.

I appreciate any and all feedback! I'm quite stuck in regards to what the issue could be!

Thank you,


Hi @8bitjack
Which of the two driver doesn't work?
What has the step on pin A7 or what has the step on pin D7?

RV mineirin

Hi RV,

The stepper driver with the Analogue pins (so A7 for step) is the driver that does not work.

A7/D7 are connected to STEP which is brought high/low which will trigger the motor to step forward one step.

I hope this helps,