Can you post a pic of your power supply? With a 4-board set, all available connections should be populated, including 9P SOU, which is unused for 2-board sets.
You did plug the monitor into the 100V outlet within the cab? And, you also have the marquee light plugged in and the marquee light comes on (or failing that, have tested to confirm there is 100V at the outlet)?
As for jump, on the wire loom that interfaces the controls to the cab, pins often become flakey on the male side of the connector. When I bought my red cab, 'up' wasn't working. That pin is no longer firmly seated in the male connector, and when plugging it into the female side, the pin for 'up' pushes out of the male side. Manually pushing it back in fixes the problem. There was also some jankiness with the grounding for the CP harness, which I don't remember the exact details of, but cleaned up by installing a quick disconnect to interface the CP to the cab at the same location as those male/female connectors. Grounding for 'jump' would be something else worth checking.