that is what i had Will, the M542 it did not work at all the L.E.D lite up but no movement.
The cheap one i have now ( in-fact i have two as yesterday another arrived ) is the 6600 micro stepper driver no name.
it has on the plate
micro step pulse/rev s1 s2 s3
nc nc on on on
1 200 on on off
2/a 400 on off on
2b 400 off on on
4 800 on off off
8 1600 off on off
16 3200 off off on
32 6400 off off off
current(A) PK Current s4 s5 s6
0.5 0.7 on on on
1.0 1.2 on off on
1.5 1.7 on on off
2.0 2.2 on off off
2.5 2.7 off on on
2.8 2.9 off off on
3.0 3.2 off on off
3.5 4.0 off off off
i have dips 5 and 6 set on, for 2.5 and 2.7
it is dc: 9 to 42vdc and is running 24volts.
As said it is very slow ( well to me it is ) the 4" chuck is turning on continuous at around 1 inch a min. a little more speed would be good but again it will only be used on the mill, but i can turn it by arthritic hand faster

Lyn.