Transmit power control problem

[Pauli Nunez EA3BLQ]

Hello there friends,

Further to my August 15 message when I asked for help to solve my lack of
power control after having solved my "Info 80" problem, I am happy to let
you know that only this morning I have finally fought the dragon to death
and my K2 has overcome its lack of power control.

I'll share my quest with you all as it may by of any help to someone
sometime. Have received some very interesting advices and have been in touch
with Gary at Elecraft who, as usual, has been very helpful. Have made a lot
of measurements and tests. Have replaced the D9 diode (an old 1N34A) and
changed to a 1N5711 and have also changed R68 to 226 ohm 1% so as to upgrade
the RF Output Detector stage to the current standards, but to no avail.

I let the matter sleep for some days and yesterday afternoon I resumed my
fight again. First of all I removed all the options, namely NB2, KSB2,
K160RX and KDSP2, reinstalling the respective jumpers. And ... alas!!. When
I pressed TUNE after setting the power to 5 watts, the Dummyload/Watmetter
read 5 watts and just a little bit more. That was amazing. The RF control
worked.  Just then I was called to attention as dinner was ready and I had
to leave my fight and clear up all the mess of tools and whatnots I had in
my workbench which, as it happens to many of us, is in the kitchen office.

This morning I have resumed the fight and the basic CW K2 still controlled
the RF output. Then I have installed the KSB2 option and ... yes, you are
right; there it was: NO ALC and lack of power control. The KSB2 was the
culprit.  Resuming, the U1 PIC (F/W 1.08b) was damaged. Have installed an
older U1 version (1.07) and the K2 works again. Now I'll have to ask Scott
at Elecraft for a replacement KSB2 F/W.

BTW. Nobody had mentioned to me that a possible KSB2 failure could be the
cause of my troubles and now, browsing N0SS new web site, www.n0ss.net , I
have downloaded a PDF file titled "Use the Serial Wrong Cable and ... BAD
THINGS WILL HAPPEN", by Gary Surrency and Tom Hammond and dated December 25,
2003, where all my K2 ailments and probable causes are commented. A pity I
didn't get it earlier, but now I know first hand and have learned a bit more
on my K2 inners.

My thanks to all of you who have contacted me on the matter. This forum is a
deep well of friendliness, companionship and knowledge.

Sorry for the bandwidth and thanks for your bearing with me.

Best 73 and best wishes to you all from Barcelona

Pauli, EA3BLQ
K2/100 # 1044
[hidden email]
[hidden email]
URL: www.qsl.net/ea3blq


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