I've got one of these boards running my CNC3040.

I'm curious because it is running on 24V and gets nothing like hot, but it sounds like most here find they get rather warm. I think I could even run mine without the fan!

It also doesn't go very fast - I can get a reliable 1200mm/min from it. I did run it at 1900mm/min but found it occasionally skipped steps.

Is this normal? Have I got something set-up wrong?

The stepper motor shows about 2 Ohms across each of the connections to the board. I don't know if this means it is in parallel or series as the connections at the motor end are covered by heat-shrink.

The big resistors near the output (I assume current sense) are 0.4 Ohms.

Measuring across one of these I get 200mV on idle and 280mV at full speed. That is about 0.7A, so does this means the motor is drawing 1.4A because it is each phase? You can see the measurements below.

This is at idle. The time base is 50us/Div


This is at full speed, but please note the time base is now 10ms/Div