The axis (x,y,z) all move just in one direction! at the beginning the machine motors span OK, but  then stuck on one direction. I tried changing to parallel port (ECP), it did not work. I work with Sherline CNC, Mach3 program. Any other suggestion ?

have you set it to sherline mode

do you mean sherline half speed, in config->pin something ? if you mean that, then yes. If not, please explain.

i've not used a sherline machine and yes that is what i was suggesting. That's all i could think of given the info you've supplied

what other info will help?
I change my settings according to this http://www.bluumaxcnc.com/Mach3-Setup.html.
I just can't figure out what can make the machine start working on one direction, when at the first steps it was ok.
I put in the MDI window the command: g01 x-5 f50 (is there something wrong with that?)

again i've no experience with the sherline, so it's hard to give specific advice regarding it. Check you have a good ground connection, and check that the direction pulse is correctly switching.

ronar,
Post your xml file and someone will take a look and see how you have Mach configured.
RICH

Here is my config.

Dont see anything wrong in your motor setup page, assuming you have the correct pins assigned it should work fine.
If  you have a voltmeter you could check on the Dir pin of each axis direct on the port. Connect the voltmeter between pin 2 and 25 and jog X one way then the other and you should see the voltage go between 0v and 5v or vice versa. Do the same for pin 4 and jog Y and then pin 6 and Jog Z.
Hood

I appreciate your suggestions. The problem was indeed the voltage. I changed the card (pic to parallel port) , and now it work :-)