It is using an L297 driver chip. How long is the duration of pulse? (this under config/motor tuning & setup). Lengthen it to 5 as a test. This is the amount of time (in microsecoonds IIRC) the direction or step signal is presented to the chip. On some machines if this setting is too low the controller never sees it. Some people use "Sherline" mode (again found in config/ports & pins/Port setup & Axis selection). Try both of these settings, first independently and then combined if all else fails. Dont forget to do a restart after changing to Sherline mode, it warns you on the page too.
Are you a member over on CncZone? If not I suggest you join there too. Not knocking Mach and the helpful people here at all. This is more of a motion control software site whereas the Zone has specific builds and electronics sections that deal specifically with the products in your board. Personally I and quite a few here enjoy both.
Btw, I did just come across this site where it looks like they have offerings to interface with the original equipment of D&M and many other brands. So if all else fails all hope is not lost. I think we should be able to work with what you have if it is operable. Nothing is blatantly obvious in your pictures like burnt or swollen electronics etc.
http://www.eaziform.co.uk/index.php?home