[Arran]

There can be any number of sources of hum other then bad filter caps, one of the most common being a heater to cathode short in the power output tube, another may be the poor routing of wiring in the AVC circuitry near tube heater wiring or open ground connections. If you are getting a station at two places on the dial this is called imaging and may be caused by the IF being out of alignment. It's also possible that the oscillator circuit has a problem and is running too fast or too slow, a leaky mica or a drifted resistor can cause this. I would also go through and check all of the carbon resistors and replace any that are more then 20% out, even some that read fine cold but are in a plate or screen grid circuit. When I overhaul a radio now I always figure on changing at least 1/4 of the carbon resistors while I change the capacitors, in a set with body end dot code resistors I figure on changing them all, resistors are just too cheap not to change.
Regards
Arran