Strange signals

[callcbm]

I have a PMDX 120 bob no complaints but having a problem with the x axis. Not sure what is causing the problem. Once a year since built x axis will only move to right with key board or mach 3 commands to the left.  I try manual keyboard command to move left it move right. Mach commands to left move right. Right command move right. Up down or y moves as it's supposed to. Shut system down wait a week and all is well. Moved the machine home for the season. and now always doing it. Always seem to do it when was hot out side. Bob is cooled with fan. Now the temp is colder and wont work.
Have check settings cable.
 Any help Please no telling me as in the past to wear a aluminum foil hat as other forums have told me

[Steve Stallings]

All of the direction signals pass through the same chip on the PMDX-120,
so I am inclined to think that chip failure is not a likely cause.

Try double checking the connections between the PMDX-120 and your
stepper motor driver, and also between that driver and the motor.

Then try exchanging motor drivers between axes to see if the problem
follows the driver.

[callcbm]

using Gecko  drives with Servos Just funny that it won't reverse on command
Thanks Randy

[Steve Stallings]

For servos my comment about motor wires does not apply, but the
other ones about the Dir signal getting to the driver, and about
swapping drivers around are still valid tests.