I've got a TRC 457 that's got some AC hum while RX'ing. Is this a symptom of failing caps in the AC/DC stage of the transformer? What I've noticed is that when I am bench testing a mobile radio in my shack (12VDC on a regulated PS) on my base antenna and no antenna on the 457 and RF gain turned down, I get a nasty AC hum on receive in the 457 while testing the other radio. I suppose I could attach a 12VDC power supply to the 457 and see if the problem goes away, but am hesitant to do so, I don't want to cause more problems by changing up how my 34+ year old 457 gets power. It's running just fine on it's own 120VAC to 12VDC supply. I had another mobile set up as a "monitor" radio, so I could try that. Looking for any input!
Thanks, 73's, happy holidays to all
Greg
Thanks, 73's, happy holidays to all
Greg