BFO test failure (K2), Part 2 of RF board test

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BFO test failure (K2), Part 2 of RF board test

Chuck-50
My BFO does is not working. The freq. counter reads 0000.0.
I have tried following other posts on the subject and checked the
voltages on U11 and verified that R98 and R99 are present, L33 is
installed correctly.
 Are their any voltage checks I can run on Q24, or L33.
Is there something else I can check? The troubleshooting guiding in the
manual is based on info messages, which I am not getting any.

I just completed the VCO voltage checks and that ran good. Everything
was within range spec'd by the manual.

Thanks, Chuck - K3TNT
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Re: BFO test failure (K2), Part 2 of RF board test

Marshall Jose
Chuck,

- Perhaps the BFO is working but the signal isn't getting past the
buffer Q24. When the K2 is in CAL FCTR mode, there should be something
close to 8V at "V ALC". If it's low or 0V, you won't see any frequency
reading.

- If D36 is backwards, that'll shut down Q24. Check D37 & D38 too.

- I like the K2 a lot, but I like L33 the least. Get out the magnifying
glass and the strong lamp and scrutinize L33 for scuffs, dings, etc.,
i.e., anything which might cause a short or an open. Do you get a FCTR
reading if the bottom cover is off?

That's all I can think of off the top.

Marshall

Chuck wrote:

> My BFO does is not working. The freq. counter reads 0000.0.
> I have tried following other posts on the subject and checked the
> voltages on U11 and verified that R98 and R99 are present, L33 is
> installed correctly.
>  Are their any voltage checks I can run on Q24, or L33.
> Is there something else I can check? The troubleshooting guiding in the
> manual is based on info messages, which I am not getting any.
>
> I just completed the VCO voltage checks and that ran good. Everything
> was within range spec'd by the manual.
>
> Thanks, Chuck - K3TNT
> <http://www.elecraft.com>
>

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RE: BFO test failure (K2), Part 2 of RF board test

Don Wilhelm-3
In reply to this post by Chuck-50
Chuck,

Do you have any way of checking the RF Voltage at TP2 while CAL FCTR is set
in the menu? An Oscilloscope?, an RF Probe?  Page on through the
Troubleshooting section until you get to the Signal Tracing part - build the
RF Probe from the parts that were supplied with the K2 kit and measure the
signal at U11`pin 6 - 0.2 to 0.7 volts is expected (follow the steps on page
10 until you find incorrect results).

The BFO signal at TP2 is not a strong as the signal at TP1 - If the counter
probe input transistors (Q9 and Q10 on the control board) are functional,
but not up to par, it is possible to obtain a reading at TP1 but not at TP2.
If the BFO RF voltages check out OK and the internal counter probe still
shows a zero frequency reading, the counter is suspect - either the probe
itself or the transistors.

Do you hear anything from the reciever at all?  Even if you hear only
receiver noise, it is likely that the BFO is working and the problem lies
with something else.

73,
Don W3FPR


> -----Original Message-----
>
> My BFO does is not working. The freq. counter reads 0000.0.
> I have tried following other posts on the subject and checked the
> voltages on U11 and verified that R98 and R99 are present, L33 is
> installed correctly.
>  Are their any voltage checks I can run on Q24, or L33.
> Is there something else I can check? The troubleshooting guiding in the
> manual is based on info messages, which I am not getting any.
>
> I just completed the VCO voltage checks and that ran good. Everything
> was within range spec'd by the manual.
>
> Thanks, Chuck - K3TNT
>

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DSP

Arie Kleingeld PA3A
Guys,

I've got the DSP unit for the K2 up and running.
It's fun playing with the noise reduction.

Up till now I haven't seen any articles on the DSP unit.
Is there anyone among us K2-users who has found out a list of optimum
settings for noise reduction? I'm very interested in SSB settings as
well as CW.


73
Arie PA3A

(K2 #3612 and it seems that I have a version 3.16 DSP soft-engine.)

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