The gentlemen in Arizona that worked on Sight-O-Tuners
has passed away and I was wondering if anyone else can
service and calibrate the Hale Sight-O-Tuner? I am new
to the forums, so sorry if this has been discussed before.
Schaff does not know of anyone that works on them.

The calibration can be checked to NIST standards yourself over the telephone. Although I haven't seen a Hale unit for quite a few years, it probably has a way of offsetting the unit to set the A 440 referance. What nature is the repair that will be needed, or is it just calibration issues that concern you? Sometimes a general electronics tech can fix issues of burned fuses/wiring/transistors and that sort of thing if it is'nt too complicated.

The big problem with the Sight-O-Tuner is the note and octave switch get worn out. This switch is not something you can get at your local electronics supply store. If you are having problem with the switches then it likely a good time to upgrade.

Mostly interested in checking calibration. I have two units
and one is having problems with the "C" drifting. How do you
check the calibration over the phone?

Check this out...

http://www.tunelab-world.com/calnist.html

Once you get it calibrated to NIST you can cross check the setting to your local dial tone and record any offset differances. You don't have to wait around for the right time sequence with your dial tone if you know what its frequency is.

The Hale Sight-O-Tuner was designed by Al Sanderson I believe.

http://www.accu-tuner.com/

I would contact Paul Sanderson, Al's son