longs motors breakout board repair need help

I bought a kit off of ebay a year or so back from longs motors on ebay. it is a 425 oz kit with the breakout board , drivers , motors and all. I finally got around to hooking it up and did a pretty nice looking job until i got to the 5 volt power supply for the breakout board. Seem a 5 volt wall wart wouldnt drive it and according to them i needed 5 volts at 20 amps which seemed high but hey an old computer power supply worked. Its an old minitech mill and i was pretty proud i got it up and running even though it needed some tweaking on the slides and alignment.

Anyway i played with it for several days as i waited to get some cutters for it and i went to show a guy at work how neat the little guy was. When i went to power everything up it didnt do anything, as i got to looking i noticed the computer power supply had been knocked off my desk and the 5 volt power supply wires where disconnected. I hooked them back up and off we went in one direction in x and y and nothing in Z. No matter what direction i jog in x and y i go the same direction, if i swap z with x or y i get the same thing , one direction out of z. Nothing changed software wise and i get the same results out of turbocnc as i do in mach3 and the wiring other then the 5 volts coming in from the computer power supply to the breakout board nothing has changed its all nice and neat.

So here is what im thinking happened some idiot came into my office and knocked the computer power supply off my desk and the 5 volt power supply wires crossed and arced. Or the idiot tried to put the wires back into the pig tail and did it backwards, 5+ to 5- and 5- to 5+. Ive disconnected the breakout board and looked for burnt traces and any signs of something like that with no luck. Of course no one will own up to doing anything like this but im pretty positive thats what happened given the guy i suspect. Any ideas where i can start to try to diagnose what needs to be fixed?

ive tried:

completely draining all voltage from the system.
replacing the 5 volt power supply.
resetting all software back to defaults.
connecting motors to a,b,c axis with no luck on any movement.

Ive got a new breakout board that just came in today from a different manufacture that ill try tomorrow but id like to fix the original if i can.

Scope the signals. That's the sure way to find out where the problem is.