It helps if the ILS receiver is turned on. Doh!
It is a Narco NAV 12 (combination Glideslope, Localizer, and VOR receivers) and as you can see in this picture the knob labeled VOL ID is also the power switch.
I assumed, incorrectly, the Narco NAV 12 powered up when the Narco MK-12D NAV/COM...