I have an 845 controller and the user manual, but I really dont know how it should operate (its likely 1970s vintage).
Both of the thermocouple gauges are working ~10torr. the gauge buttons light when pressed, but there is no tube attached.
I dont have a way to do that at the moment.
The main operational question is whether the digital display should light with no tube connected? (it does not).
Is there a way to test the display?
Or point me to a better forum or user.
Kevin