Rumba Board problem

[ex-egll]

Hi, my machine had been happily printing, but the next time I did an ABL the Z-Axis would only move in an up direction.

I went to the menu on the LCD to try to to move the Z-Axis that way, and again it would only go up.

I swapped 2 motor plugs around on the Rumba so the X axis controlled the Z motor and vice versa. When I commanded the X-axis to move, the Z-Axis moved, so it seems the motors are OK. When I commanded the Z Axis to move the X-Axis moved in one direction only.

I put the motor plugs back in their original locations, and swapped the X and Z motor driver boards. The X axis worked, the Z only moved one way, so it looks as though the driver boards are OK.

I reloaded the firmware, but that made no difference.

To my mind this suggests an issue with the main board. Next thought was to move the Z-Axis driver board and motors plug to either the E1 or E2 position on the Rumba.

My questions are:

How do I (or can I) remap the Z axis to E1 or E2?

Is there anything else I should try?

Thanks