Carlos, et al.
After removing the magenta power wire from the logic board, the tone
was gone! So it is the frequency counter. I then checked the 1000mfd cap and
it tested fine for capacitance, ESR, and leakage. I disconnected C2, 560pf,
that connects pin 16 of MK50398N to Vcc. The tone was gone. The receiver
is working fine but in my haste in putting it back together, I was off by one
pin on the Preset Amp board to Display Board connection. The frequency
meter was reading weird. Correcting that, all the bands appeared fine except
the 10mhz band. It is picking up WWV on 10 mhz but it reads 28.0 mhz.
The whole band now read 28.0 to 28.5mhz instead of 10 to 10.5mhz.
I need to check the components on the Preset Amp board. Any suggestions
are welcomed.
Lyman KK6LPW
-----Original Message-----
From: forum4ll <forum4ll@verizon.net>
To: tentec <tentec@contesting.com>
Sent: Tue, Jan 1, 2019 12:05 pm
Subject: Re: Omni-D with an Annoying 1khz Tone
Carlos,
I will do that when I get into the shop tomorrow. From your suggestion,I found
these two other things I can look for in the frequency counter:
1. https://www.eham.net/ehamforum/smf/index.php/topic,26529.0.html
2. The digital whining from DL1CYP's Ten-Tec 544:
https://www.eham.net/reviews/detail/735?page=2
Thanks,
Lyman, KK6LPW
*************************************************************************************
mmm... digital noise from the frequency counter?
Can you cut the DC suply to that module and tell us what happens?
73,
Carlos VK1EA
On Tuesday, January 1, 2019, <forum4ll@verizon.net> wrote:
>
> Happy New Year everyone!
>
> This Omni-D that I've been working has an annoying tone that can be heard
across all bands and it is in the background. It measures about 1khz and
will vary harmonically when I slowly turn the VFO thus changing the 100s
hertz digit in the display. The waveform changes back and forth between a
sinusoidal and a rough sawtooth. I can mask this tone by turning up the Rf
gain but its still there. It is pronounce when the Rf gain is turned down.
>
> Does anyone know what the problem might be? Could it be in the VFO or
possibly the IF section?
>
> Lyman KK6LPW
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