Stepper only going in one direction

Hi
My Denford Microrouter has been working fine until this morning. When homing the X axis, the cutter went off in the wrong direction until it reached the far end (away from the homing switch) and is stuck there. When I try to jog it in stepconf it won't move (the motor just grinds against the end)
I'd like to narrow down the source of the problem - the software configuration hasn't changed but maybe there's an issue with the parallel port or the cable. Or it could be on the controller board or the stepper itself. I feel that the Hal meter should be able to help me here, but I'm not sure what to do. I've checked that the homing switch is working OK but need help to go further
Thank you

I did an obvious thing which was to temporarily switch round the X and Y pins in stepconf. The problem was still there. Must be a hardware problem on the router, I think

if you add to your gui (if axis) a "debug panel" using these for example ... linuxcnc.org/docs/html/gui/pyvcp.html#_leds ... you can easely debug these hardware problem if exist or not ....

regards

Stepper drives/motors are notorious for going in only one dir when poorly grounded or not grounded at all. Possible cause; joint corrosion, loose crimping, etc etc. 1. Rule out ground with a DMM, ensure you have <0.5ohm.

Thanks. Do you mean the metal body of the motor needs to be grounded? Or one of the pins?

Stepper drive return GND particularly. While in there you might as well do a check on the DIR pin too. Ensure you have (1)continuity and (2)low resistance between the drive and the control board.