PWM output on CNC BOB

[magicniner]

I feel I am either missing some concept or being very stupid.

You are in the process of learning why cheap hardware is cheap and that some of what you are paying for with better, more expensive products is adequate documentation and support ;-)

[jolyonjenkins]

You are in the process of learning why cheap hardware is cheap and that some of what you are paying for with better, more expensive products is adequate documentation and support ;-)

Not the MOST helpful and specific piece of advice :-) I didn't buy this board, it came with a mill that someone else had retrofitted, and I am well aware of the danger of cheap hardware.
I did find a manual for it

https://www.dropbox.com/s/gfq4isvihn...rd-EN.pdf?dl=0

which I hope someone in the future might find useful