[Elecraft] Thumps or pops and now a dead sidetone - What next? de AL7FS (long)

[Jim Larsen - AL7FS]

My K2 is slowly fading by inches.  I have been working with Gary on my
problem but now it has escalated to a dead sidetone.  Here is the story.

I wrote to Gary and described pops or thumps at the end of a key down,
i.e., if I key a string of dashes as each dash ends the headphones or the
speaker thumps or pops at the end of each dash.  Sometimes it did not do it
and at other times the rig was not very useable it was so bad.  I never
could identify what variable made it happen or not happen.  Gary responded
as follows:

"I'd try another power supply or power cable. Make sure the DC
connector fits well, and the size and length of the cord is 3 ft of #16 or
#18 AWG.  If there is too much voltage drop or droop in TX, you might be on
the edge of adequate regulation.

**  DC cord is a short length and probably a #16 but at least #18.  Voltage
per the rig's voltmeter is 12.7 volts.  That is about right as I am running
my power supply a bit low to not overcook a 40 amp hour gel cell being
floated.  I have both the PS and the gel cell on line at all times.  No
voltage sag.

Also see if changing the t-r delay in the Menu makes any difference. You
could have marginal muting.

**  I reduced the t-r to zero and it seemed to reduce the thump and I liked
the setting better (full QSK versus semi-QSK).  Last night the thump was
back. (More detail below.)

I've had RF get into some types of headphones and cause weird stuff like
this.

** This occurs both in headphones and in the K2 speaker.

Check your antenna cables for poor connections too. I've had that problem
on
several occasions.

**  I tried a different cable and saw no change.

73, Gary AB7MY
=====================

Yesterday I built up the audio filter and installed it in the K2.  Seems to
work fine.  All setup steps worked as advertised.  Then the thump started
up again.  (Note: may not be relevant but I raised max current to allow
short test at max output, about 15 watts on the K2 meter.  Keyed and
checked then backed the power back down to 5 watts.)  I played with the
audio filter a bit more and was punching buttons here and there.

Finally the sidetone quit.  I researched my 33,000+ Elecraft message files
and found that it is possible to have set the sidetone source to the wrong
source.  I checked.  It is ok.  I changed it over and changed it back
several times.  I powered up the rig and down several times.  I unplugged
the rig several times.

The only thing left that seems easy is to open the top and flipped the AF
in and out a few times.  I will do that.  Question: Should the AF go to off
when the rig is turned off?  Seems awkward to always have to turn it back
on every time I turn on the rig.

One owner did a full reset of the CPU.  Ugh.  I will have to read to see
what notes I have to make before I reset and just how to do that.  I can't
remember the keystrokes for the reset at this point either.  I would mind
if someone can let me know what to do and what not to forget so I don't
have to do Spectrogram and everything else all over again.

On a positive note...with the sidetone totally dead, the thump or pop
problem has gone away.  :-)

Could the thump or pop have been a precursor to something about to fail? 
And now it has?  Doesn't seem likely but...

I am trying to get the K2 ready for my trip to San Diego and yesterday I
just bought a ton of extra accessories.  I hope to have this fixed in the
next day or two before the NB, SSB, tuner, battery, mike, etc. arrives.

Thank you list members for tolerating my public message versus just working
only with Gary (Thanks, Gary).

73, Jim
-- 
Jim Larsen, AL7FS, Anchorage, Alaska
(BP51cc) - 61.101 North, 149.824 West
ex-WA0LPK AK-QRP#003  SOC#003  10-X-#12094   
mailto:al7fs@arrl.net - http://www.qsl.net/al7fs/