[R-390] 60 Hz on Audio - Cause Begins to Reveal Itself

[odyslim at comcast.net]

 I think it is your power transformer.. I have a lot of EAC transformers
that work fine but really hum along.

Regards, Scott

----- Original Message -----
From: Craig C. Heaton <wd8kdg at worldnet.att.net>
To: r-390 at mailman.qth.net
Sent: Fri, 19 Jun 2009 21:04:58 +0000 (UTC)
Subject: Re: [R-390] 60 Hz on Audio - Cause Begins to Reveal Itself

Jon,

I've been following this thread for a while, thought the quest for a quiet
radio would have been solved by now. So, your first post, you stated the
receiver has been recapped? Ok, what did you recap? What type of caps?

My stab at fixing this pest, did you replace C103? In the past, it is
referred to as the bathtub cap. This item is mounted on the inside back
panel inside a little metal container shaped like a bathtub, 50mF @ 50V. One
end is connected to ground and the RF gain pot, the other end to terminal 1
of TB102. 

The little beast is on the cathode bias line of a bunch of toobs.

73's
wd8kdg
Craig
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