[462ron]

Hi Ron, since I don’t profess to be an engineer, I will give my theory as to how your tuning indicator works so here goes. Since the plate circuit of the 6J5 tuning indicator tube goes to ground through the secondary of transformer #93 instead of back to some B+ supply, that puts the tube in parallel with the secondary. As the station gets stronger when tuning, the grid goes more positive or less negative from the cathode of the 6H6 AVC tube, thus making the tube more of a load across the secondary. This will reflect back to the primary as a lower impedance in series with the indicator bulb #94. This in turn would allow more current through the bulb giving a brighter response to an increasing signal strength, exactly what you are experiencing. Others may disagree with my theory.

Ron