[Milsurplus] URM-25D Hum reduction

[john p hutchins]

All - I defer to the clan

Thank out ot Ashley40 for help-

I have completed the re-capping of my URM-25D, performed all the Voltage 
and resistance checks, and aligned the unit using my recently calibrated 
frequency counter.  Re-calibrated the RF and modulation Meter settings.  
Its dead nuts on all bands as far as the Eye can tell, the Dial tracks 
well with the Frequency counter!
Here is the status:
1.  -> There is HUM in the audio circuit, audible at ~1/2 volume.<-
2.  The audio modulation test frequency of 400~ and 1000~ were checked 
by the counter and are 393~ and 989~ no way to adjust. Sa-La-Ve

I suspect the 60~ hum may be playing with the modulation frequencies?
I have moved any heater wires as far as possible from the grids of the 
Audio Modulator.  A small reduction was noticed.
What's next?
Should I put DC on the Heater circuit and say done?

Thanks
Hutch