I have a Royal 97 which looks just like the Royal 790 shown above. The schematic in Sams TSM-58, which I will scan, is for the 790.
AVC voltage from the detector is applied only to the 1st IF stage. Then, voltage from the emitter of the 1st IF stage is fed to the RF and Mixer stages as a low impedance. BTW - in the "DF" mode, AVC is disabled.
All transistor radios of this vintage need their electrolytics changed.
The picture is from a forum member's website showing his collection of direction finder radios. It has some very interesting radios and descriptions.