[R-390] R-390 Antenna Relay Chatter

[Barry]

Jim, 

Actually the buzzing is not all that quiet. I have at least one 20k/V analog meter that I'd planned to use to check that and should be able to determine a suitable resistor from there. 

Thanks, 
Barry - N4BUQ 

> From: "Jim Whartenby" <old_radio at aol.com>
> To: "n4buq" <n4buq at knology.net>, "R-390 Mailing List" <r-390 at mailman.qth.net>
> Sent: Friday, October 21, 2022 2:18:23 PM
> Subject: Re: [R-390] R-390 Antenna Relay Chatter

> Barry
> I would think so, the buzzing is most likely the antenna coil winding vibrating
> at 120 cycles. You must have good hearing!

> Out of curiosity, what is the AC voltage into the bridge rectifier and the DC
> voltage output from the new rectifier? I am assuming that you are using a DVM?
> I wonder how your reading will compare with the meters listed in the
> preliminary manual?

> The TS-297 is a AC-DC voltmeter with 1k ohms / volt
> The TS-352 a VOM is 1k ohms / volt AC and is either 1k ohms / volt or 20k ohms /
> volt DC, switch selectable
> The TS-505 a VTVM is 20 megohms / volt on most of the DC voltage ranges

> I'm sure that since the impedance of this power supply is pretty low the DVM and
> the three meters above should agree closely but higher impedance circuits
> should show vastly different readings due to circuit loading.

> Regards,
> Jim

> Logic: Method used to arrive at the wrong conclusion, with confidence. Murphy

> -----Original Message-----
> From: Barry <n4buq at knology.net>
> To: R-390 Mailing List <r-390 at mailman.qth.net>
> Sent: Fri, Oct 21, 2022 1:32 pm
> Subject: Re: [R-390] R-390 Antenna Relay Chatter

> After replacing the selenium rectifier with a full-wave silicon bridge, the
> antenna relay is no longer chattering. Truthfully, I'm not certain the
> chattering was the old rectifier and was, more likely, a failing FL101;
> however, now that I can power up around FL101, the antenna relay still gives
> off a distinct buzzing sound. Since it's being fed a rippled 120Hz DC, is that
> expected?

> Thanks,
> Barry - N4BUQ

> ----- Original Message -----
> > From: "n4buq" < [ mailto:n4buq at knology.net | n4buq at knology.net ] >
>> To: "R-390 Mailing List" < [ mailto:r-390 at mailman.qth.net |
> > r-390 at mailman.qth.net ] >
> > Sent: Friday, October 7, 2022 11:59:10 AM
> > Subject: R-390 Antenna Relay Chatter

> > When in STANDBY, the antenna relay in my R-390 produces a bit of chatter. Is
> > this normal? I see where that relay is fed, unfiltered, from CR801 which, from
> > the pictures in the manual, appear to be a stack of selenium diodes and I'm
> > wondering if that rectifier stack might be a problem. Anyone know what to
> > expect from that relay in STANDBY and, perhaps, what I'm seeing might be
> > normal?

> > Thanks,
> > Barry - N4BUQ
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