stepper controller

[vicsrc]

I am using a Univelop control board with a vexta stepper motor on my Z axis.
When I drive the axis in the up direction or the down direction sometimes the motor will drive in the wrong direction. Sometimes it will only drive in one direction and tapping the up or down keyy several times it will drive up and down with the same key.
What am I doing wrong and how do I correct this problem?

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[Georgecape]

I have exactly the same problem.
If I wait one second between arrow keys (up or down) it works 100%.
But when running a program the instant change in direction is correct per the DRO but the Z-drive continues in the wrong direction.
When I swop the Z with the X there is no difference. But the horizontal X and Y drives with small Nema 23's are perfect. The Z-drive is the largest Nema 23 available (3Nm).
Can the BoB be the culprit? Or the printer cable? I've already replaced the microstepper - no improvement.
All parts ex-Banggood. 24V system. Mach3.

[datac]

I have exactly the same problem.
If I wait one second between arrow keys (up or down) it works 100%.
But when running a program the instant change in direction is correct per the DRO but the Z-drive continues in the wrong direction.
When I swop the Z with the X there is no difference. But the horizontal X and Y drives with small Nema 23's are perfect. The Z-drive is the largest Nema 23 available (3Nm).
Can the BoB be the culprit? Or the printer cable? I've already replaced the microstepper - no improvement.
All parts ex-Banggood. 24V system. Mach3.

These things are usually caused by incorrect or incompatible step and direction signals. They can be more complicated than some realize, with drivers requiring specific timings for leading and falling edges, step pulse level and durations and even direction change delays.

If you do not have a controller that does not allow you to completely dial in the requirements of ANY driver, you could be chasing this for some time. It is one of the reasons there have been so many "BOB" boards offered on the market to stabilize/clean/alter the signals specifically being sent via parallel port via controls such as Mach3.

[Georgecape]

Thks datac. I have a spare BoB which I'll try today.

[Georgecape]

Swopped the BoB out with a new one but no improvement at all.
I'll see what the local suppliers have on offer and continue changing BoB's yikes.

[Georgecape]

Installed new smarter microstepper controller on the Z-drive - zero change.
That is now 3 BoB's, 3 stepper controllers and a new printer cable.
Up and down still erratic.
Will appreciate any help

[Georgecape]

Problem solved. Loose wire in the aviation type connector to the control box.