2 out of the 4 stepper drivers I recently received arrived broken. A quick check with a multimeter showed that the potentiometers used to set the maximum current were defective. Without time to wait for replacements, and without this package of smd potentiometer on hand, I decided to just solder two 0805 resistors in place.
The values are calculated using 
where 
is the output voltage of the resistive divider consisting of the potentiometer and R1(30kΩ), 
is the maximum current and 
is the current sense resistor (R4 and R5 in the image below; 0.1Ω).
