When checking for 24 VDC on S1, the voltage comes in on S1-8. There is a bridge between S1-8, 6, 4, 2. So if you have it on S1-8, and not on another, it could be a loose screw. Depends on what type S1 you have. If is the MK1 style, the "bridge" is several removable links. They sometimes get...