[Amps] Alpha 76A - 120hz hum on 160m only

[TexasRF at aol.com]

Jim, it is possible that the hum is present only in your local receiver and 
 not actually being transmitted.
 
As a test, you might have a local listen to the signal and give you a  
report.
 
73,
Gerald K5GW
 
 
 
 
In a message dated 10/16/2013 11:59:55 P.M. Central Daylight Time,  
audioguy at q.com writes:

After  replacing the filter caps and equalizing resistors, I fired up
the 76A  today on 40m and had a couple of nice contacts. The 120hz hum
problem  *appeared* to be gone. The spectrum analyzer showed a nice sharp
clean  carrier, with no "funnies" in the sidebands or for a few mHZ
either  side.

And then I tuned up on 160m. 120hz hum like crazy on a carrier,  hum 
distortion on SSB. Unusable.

Tuned up on 75m, clean as a  whistle.

So - it hums like crazy on 160m, but not on the other  bands.
Plate choke and/or bypass caps? It loads up fine on 160, just hums  like
crazy.

Ideas? (other than exorcism)

Thanks,
Jim  N7CXI
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