[Elecraft] My K2 transmitter sounds odd - it was RFC15

[Hisashi T Fujinaka]

Thanks for everyone's help on this. I spent most of the day with a lot
of test equipment and I found out the following:

You can break RFC15 and have no DC going into U4, the Synthesizer PLL,
and the radio can mostly work. CMOS parts can get power from signals on
the other pins through the substrate.

In my case, the PLL would lose lock and regain it quickly, giving it an
odd sound as I tuned across a carrier, sort of like "bloop-bloop-bloop."
I thought, "Well, it's a kit. It's probably supposed to sound like
this." Once I replaced RFC15, it tunes smoothly with no jumps.

Also, the transmitter output looked fine on an oscilloscope and on a
spectrum analyzer but sounded like hash. The nasty signal I heard on my
IC706 was really the Elecraft. The spot would also generate a hashy
signal.

I was also convinced things were fine because all of the testing and
calibration worked fine. The receiver sounded great (besides the jumpy
synthesizer) and I heard more signals on 20 and 40 than I was used to.

So, I'm sure I'll get a half-dozen people saying, "I've never broken
RFC15 and I've built a hundred K2s," but we looked at it under the
microscope and it appears to have cracked just from bending the leads. I
replaced it with yet another toroid, 10uH rather than 100uH. It's all I
had; I hope that's enough.

On Fri, 9 Jul 2004, Hisashi T Fujinaka wrote:

> Last night I tried to get on the air with my new K2. The receiver
> sounded great, and I heard lots of activity on 40M CW and 20M SSB.
> However, when I tried to listen to my transmitter with my IC706, it
> sounded raspy and nasty. Looking at the signal with my 'scope told me
> very little (nothing visually out of the ordinary) and my quick scan
> through the troubleshooting guide didn't tell me much. Nothing changed
> when I used a dummy load instead of my possibly mistuned antenna.
>
> So, back on the bench it goes.
>
> Anyone have any hints?
>
> (I had to hook up a straight key because I still haven't learned how to
> use the paddles with any repeatble success.)
>
>

-- 
Hisashi T Fujinaka - htodd at twofifty.com
BSEE(6/86) + BSChem(3/95) + BAEnglish(8/95) + MSCS(8/03) + $2.50 = latte