Start from Node 8 (upper left), this is the node board that talks CAN bus to the CPU board. The CAN bus is robust and has no issues.
The node board has 2 SPI hosts (the purple wires coming from it). The lower wire, cn3 leads to the problem. If you follow it, it goes to node 8B, 8C, 8D and eventually to the motor control board 8E. If any of these boards or their connectors malfunction, the motor control board is dead in the water.
If we look at the video I posted again, the mode lights above the flippers seem fine (that's node 8b) but the sign over mode hole and arrows pointing to right ramp and right orbit flicker badly. It's very likely that 8c or 8d has a bad connector.
