Hi Jimch52,
sounds like the 'soft limits' have triggered. On the 'program run' screen there is a button to turn soft limits on and off. I you turn
them off then you should be able to jog all axes in any direction. With the limits on Mach will restrict your jog/move options to
those that are in the limit zone ie either direction but disallow any direction movement on any axis that takes you outside of the of the
zone or further out of the zone than you already are!
The soft limits are configured on the 'homing/limits' configuration page. Without home switches and referencing at turn on soft limits
are a bit useless.
For a time I was blaming my handheld jog controller for not being able to drive my Y axis in the negative direction when in fact it was
the soft limits trying to prevent me from crashing the axis. Once I realised what was going on I turned the limits off and crashed
the axis ALL BY MYSELF!! LOL.
Craig