I have a "whole home humidifier" next to my furnace that I think has stopped working.  It's very dry/staticky in my house and there's no water or condensation coming out of the drain tube.  I closed then opened the shutoff valve that runs water to the unit.  Other than that, I don't really know what else to troubleshoot, if there's even anything to do.  The furnace and humidifier are less than 6 years old (my first house) so I don't know if these things are considered disposable or what.

Anything I can try myself before calling a repairman out?

probably clogged up.  look for the solenoid, undo flair nuts to see where water is getting to.  If you had a meter I would say look for 24 volts on the solenoid coil, other than that, hard to walk you through something if you dont have the basic skills and knowlege.