Hi Jen,
Thought you would have tested the wires continuity and connection points but worth a try.
what i would like to know is what the BOB expects in the way of input from the parallel port. is it just a nice square 5v "wave" for "step" and the same to change "dir"?
The direction signal is either high or low and remains in it’s set state until another command tells it to change (axis move in opposite direction). The step signal is a square wave pulse which Mach allows to be altered in terms of width and active high/low.
Most BoB's require a 5 Volt peak to peak signal here and some computers, especially laptops, only output around 3.3Volts and these do cause problems.
Most PC parallel ports are more than capable of sourcing 10 mA per pin so would light your BoB leds but it is risky to over do it and possibly damage the port.
Just a thought here but have you tried Config / Ports and Pins - check the ‘Sherline ½ Pulse Mode’ box ? this alters the pulse width and may cause different results.
Lets hope it is the BoB and that your new one solves the problem.
Tweakie.