I'm pretty sure I read the voltage correctly the first time, with the module jack fixed I now measure -10.4 on the orange wire.
The Selectone board has a few traces where the solder is missing in places, but when I test end to end for continuity the ends connect. Does the solder need to be continuous on a PCB trace for the 5066 to work properly, does the etched trace still conduct? Is there a way I can send a photo? The 'insert an image' icon does nothing.