[R-390] R392

[Barry]

I've never owned one, but by the pictures I see on the internet, the 392 doesn't have a diode load connection brought to the outside like it's bigger cousins.  If there's a similar pickoff point inside, you could feed that to an external audio amp and see if the problem persists there.  Alternatively, you could take the IF output and feed that to a general coverage receiver (assuming the IF on the R392 is 455 kHz or some other frequency readily receivable on a general coverage radio).

If the problem doesn't persist listening on those alternative paths, then the problem is downstream from that point so that might at least narrow it down a bit.

72 and good luck with it,
Barry - N4BUQ

----- Original Message -----
> From: "Guido Santacana" <gsantacanav at gmail.com>
> To: "Bob kb8tq" <kb8tq at n1k.org>
> Cc: "r390A" <r-390 at mailman.qth.net>
> Sent: Monday, June 19, 2017 8:45:04 PM
> Subject: Re: [R-390] R392
> 
> The more I hear it, the more it smells to an audio circuit problem. It
> takes about 5 minutes for the noise to appear after turning on the radio.
> After reading both Charles and Bob's recommendations sounds like a cracked
> resistor but could be any of the other alternatives. Tomorrow the radio
> goes on the work bench ( in my case a small mechanics folding bench from
> PepBoys). I will report my findings. It's been quite a while since my last
> R392 repair.
> 
> Thanks for the recommendations gentlemen. Highly appreciated.
> 
> Best 73s
> 
> Guido
> 
> Guido Santacana KP4FAR
> EAC-R390A, Steward Warner-R392
> 
> On Mon, Jun 19, 2017 at 6:59 AM, Bob kb8tq <kb8tq at n1k.org> wrote:
> 
> > Hi
> >
> > I’d put “60 year old unsoldered connection” on the list along with
> > “cracked resistor”.
> > Both are a poke around a bit and listen to what happens sort of thing.
> >
> > Bob
> >
> >
> > > On Jun 19, 2017, at 12:12 AM, Charles Steinmetz <csteinmetz at yandex.com>
> > wrote:
> > >
> > > Guido wrote:
> > >
> > >> There is some popping before it come back
> > >> so I suspect a bad cap in the audio section.
> > >
> > > If the volume control has no effect, the problem would appear to be in
> > the audio section (V606, V607, V608 and associated circuitry).
> > >
> > > Bad cap is certainly one possibility, but don't forget the most common
> > source of such problems, namely noisy contact between tube pins and their
> > sockets.  To check, just put your finger on top of each tube (one at a
> > time) and wiggle it a little.
> > >
> > > Best regards,
> > >
> > > Charles
> > >
> > >
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