all of the schematics are in the user manual. I've attached the 3 manuals I have for this manual.
to more directly answer your question: no, there are no position sensors. However, there are two encoders on the spindle, one with 32 ticks per rev, and other other with a single tick per rev (for timing, specifically thread cutting).
I got my machine up and running with the original controller, but decided the parallel and serial interface, and the ancient software wasn't worth the hassle. I'm in the process of replacing some of the control electronics with a PoKeys57CNC controller, which supports mach3 and 4, and has usb and ethernet interfaces. hopefully that will bring this machine fully into the modern era.