OK, XLR Pin 1 connects directly to the chassis, resolving my empty XLR Pin 1 question.
Figure two shows J9 pins 1 & 2 audio input connected to XLR pins 2 & 3, as well as pin 4 ground going to chassis. Pin 3 nAMPON is not shown, but also goes to chassis, yes?
I do appreciate your help!