The thumbscrew screws into a threaded hole in part # E700012 (screw terminal, right-angle PCB mount), which is soldered to the PCB, and is shown in the parts list at the bottom of page 5 in my recent manual. >How does thumbscrew connect to E1ground terminal (pg 23)? Looking at Figure 13 (pg 20). >My chassis has a hole in which the thumbscrew slides in/out of E1. What keeps it secured to the chassis?