So I have a neo geo 138-in-1 cart. these are the ones with the sub board connected. I have it connected to an mv-1 board in a cab.

The problem I am having is when everything is connected and I plug in the cabinet, I get a garbage screen displayed which is supposed to be the selection menu.

If I disconnect the jamma harness from the board, plug in the power to the cab, and then connect the jamma back to the 138-in-1, it works fine. I would like to be able to power on the machine and play without having to do this step of reconnecting the jamma cable first. Anyone else had this issue? Or any idea of what I could do for a solution? I will upload pics later of the symptom I am describing.