Quoted from PinMonk:The dead simple way to isolate your problem is to swap node 8 and 9 (changing the dip switches so each knows its new role) and see if the problem moves to the left halfpipe (which is on node 9, CN12, pin 2). If after the swap your problem remains on node 8, it's the wiring or connector itself. If it moves to the node 9 (which was node eight) it's the node board pins, most likely.
Do pro models have node 9?
Rob