The 6CW4 is the first RF amplifier stage, so if that goes bad, the signal gets no farther except in local mode. You have a local-distant switch which biases the 6CW4 into cutoff in the local position and the signal goes to the second stage via the neutralization network in the local position. There are a few other weird design features in this set.
The AFC uses an NE-2 neon lamp as a voltage regulator for the AFC diode.
The supply to the oscillator and 1st IF screen has no decoupling other than the capacitor to the bottom of the 1st IF transformer.
The IF stages are bridge neutralized by having the screen bypass capacitors go to the bottom of the IF plate winding. My Fisher KM-60 uses the same design.
You may find some deviations from the published schematics with the inclusion of a stereo decoder plug that is 11-pin rather than the 8-pin shown on the schematics. There is a diode detector network similar to the one for interstation muting but of opposite polarity whose output goes to the MPX section and this is not in the published schematics. The stereo light that is shown to come from the selector switch in the published schematics actually appears to come from the MPX decoder.
The published schematics omit the value of C74 at the signal input to the MPX decoder. It is 0.01 µF 5% because it is part of the SCA filter tuning capacitance.
Whether by accident or design, someone had replaced the last 6AU6 stage plate supply resistor in my unit with a 120 ohm rather than the designed 1200 ohm resistor.
Someone has added a capacitor across the cathode resistor for the first 6AU6 stage, so this and the last item may be someone's attempt to hot-rod the IF stages.
My tuner is badly misaligned, so it is not a good example of how the unit should sound but I will get out my trusty SG-165 at some point, I just have a lot of things to do. How did I ever find time to go to work before I retired? It takes a large signal (from a signal generator in my case) to get the meters to move, so dead meters may not be dead after all.
The Citation III was featured in the April 1961 issue of Radio Electronics. It was the winner of the Electronics Illustrated shootout of 11 FM tuners in the November 1961 issue. It beat all other tuners in harmonic distortion and signal-to-noise ratio and came second in most other specifications. It was the most expensive in the test and it still commands a high price today. No one was looking to pinch pennies in this design except maybe on the cheap wafer tube sockets and the corroded antenna input terminal strip. The dial cord idlers have plastic bearing inserts – something I have never seen elsewhere. You can find these articles here:
http://www.americanradiohistory.com/