Author here if you have any questions :-)
But because of the servo loop feedback, most of the components aren't critical to accuracy. (Note that the internal power supplies are entirely unregulated.) If the motor slows down, for instance, it will still end up at the right location. The potentiometer is really the critical part, but it shouldn't change very much. And if it does change, as long as the resistance changes uniformly, it will still be okay.
This is an example of the pitot/static inspection procedure for a Cessna Citation Sovereign. The procedure itself begins on page 9 of the PDF.
> The unit is powered by 26 volts, 400 Hz, a standard voltage for aviation.
Any idea as to the history as to why this is the case?
I assume higher voltage is useful for lower amps? But why 400 hz?
Seems odd to use such a high voltage if components such as this must have internal transformers?
In aviation, that matters because weight matters.
The downside is iron losses become bigger (heat lost in transformers). In a plane that typically doesn't matter because you aren't worried about losing a couple of watts of electrical power.
In today's world, it is irrelevant because all voltage conversion is done solid state (which is easier from DC), and all motors (of new designs) are brushless and therefore prefer to run from DC.
For mains voltage we use 50-60 Hz because lower frequencies work better with very large AC generators in power plants and, and lower frequencies are more efficient to transmit long distances.
https://en.wikipedia.org/wiki/CDC_6600?wprov=sfti1
CDC had a defense contract for early air data computers, used in the F-18. That business survives today as part of General Dynamics.