I had exactly the same problems over the weekend. All axes drove well using pins 6 and 7 (Z) on my BOB. Y (4 and 5) could be tuned to run slowly, but X (2 and 3) was rubbish. As I had already tested the 3 steppers and drivers, my thoughts were that only the BOB or Mach3 could be the problem, so I substituted a direct connection BOB and all drives were OK. Even managed to draw Roadrunner!

When I find out the source of the problem and I suspect it is noise from the drivers or the BOB, I will post it in this thread.

Ian

Thanks Ian.
I tried this out again and my results were different this time or maybe I was simply not understanding what was happening the first time.
My Z runs good regardless of the pins, but the other two go both ways with one arrow key. Push the key several times and it will switch directions. Sometimes it does it with just two presses of the key.
I do think I just need to break this all out on a table and start from scratch to confirm that I'm not getting ground loops or electrical noise.
I do look forward to hearing how you fair with yours.
Thanks.

Problem located!!!!! I would holler YIPEEEE, but I don't feel good about not finding the issue sooner. Pretty much a no brainer.
I had took such care with this build. I used good techniques and went very slow checking everything multiple times.
On my first build, I had inadvertantly zapped a Xylotex when a motor wire touched the case. The only wire I didn't have tape on. It was fixed at no cost, but I really wanted to avoid that sinking feeling with this one.
Well....to the point.
I bought these connections off Ebay because I wanted an easy way to plug the motors in. They are nice and easy, but somehow two of the pins got bent to the side from the motors. Of course it couldn't have been the unused pin or a shield pin. They are on the other side of the plug. It was the same pin in both cases. One of the coils wire.
Anyway, problem solved. I thank you all for the help.
Now we know that if the motors turn both ways with just one key, it could be a loose wire connection.
 

Glad you are sorted and thanks for posting the problem, it may help someone else later on.

Hood

You wrote :-
"Now we know that if the motors turn both ways with just one key, it could be a loose wire connection."
That's one to note for future debugging. Great to hear that you got it sorted. It's the simple ones that get you every time.
My problem is definitetly noise. I can see it on the 'scope. A new BOB is on the way, I will post again if this cures it.

Ian

Thanks Guys. It was definitely an adventure.  I did learn a lot from it. I also shielded all my wiring. Thats good to have. Looks neat and won't hurt anything and may actually help prevent problems in the future.
The shielding came from Mcmaster Carr and may be worth looking into. It's very reasonable. It does expand larger than they list, but then relaxes to the size listed.
I have at least one more machine going after this one. That will give me three. The next one is a mill. I think 203V's and possibly a G100 will be on the menu for that one. I may want more than just three axis.
Thanks again and good luck with the noise.

I just thought of a test that would have prevented this.
Use an ohm meter to test the motor coils just before hooking them into the drives. I tested them on just the motors. Then I tested them with all the cables. I also tested the wires to the plug. Everything was fine. I neglected to test them once the cables were plugged in though.
I'm bloomin lucky I didn't blow a couple of gecko's.
I do feel much better now. Hopefully my ranting on here will help someone prevent this mistake in the future.
I knew it was something simple. 

Just an update on my noise problem. It was due to an incompatibility problem between the CNC4PC C11 BOB and the stepper drivers from Routout (UK). Arturo Duncan sent me a replacement C11 board but no change. He then sent a C11G, which is not fully optoisolated but has the spindle speed controller buit in. This cured the problem and my little mill is now running fine. I will post some photos in a new thread.

Ian Ralston