Chirp/Raspy problem with new K2 #5116

[Roger Marrotte]

I just finished "Alignment and Test, Part II".  All went well.  All test
were passed.  All alignments went well.  The filters were peaked, etc.  This
is the third K2 I've built.  This time all was perfect the first time.

My problem is this. When listening to a CW sig on the air, pushing almost
any button or turning most knobs causes a raspy/chirping sound from the
received signal that doesn't go away after the knob/button has been touched.
I've noticed the following:

I'm not near any power supply.  Turning the KEYER, POWER, AF GAIN and RF
GAIN knobs does not cause the problem.  Turning any other knob or depressing
any other button causes the chirping/raspyness.  It almost sounds like
digital interference sometimes.  I discovered that turning the spot function
on causes the received signal to be very very raspy.  At the same time the
spot tone is pure.  Subsequently turning the spot function off causes the
received signal to clear up with no noticeable rasp/chirp, until one of the
knobs/buttons is turned/pushed again.  This is repeatable.  I've tried using
a battery with no change.  I'm using the 12v supply (ASTRON) that works fine
on my Yaesu and has worked fine for two other K2s.

I've repeatedly checked all boards for unsolders leads, etc.  The AF pot is
in the correct position.

Again, all test passed.  All values were stable and well within range.  CAL
PLL was run.  CAL FIL was performed and filters set to table values (for
now).  BFO range was 4.4.  VCO voltage readings were all in range.  The 4Mhz
oscillator was set to 4Mhz.  In short there were no problems.

I sure hope someone has an idea.

Thanks,  Roger, W1EM


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[Roger Marrotte]

Thank you, thank you, thank you.  You were right.  Apparently the end of
RFC15 attached to the cap was either not connected or had a poor connection.
I touched up the connections with the iron and it works like a charm now!
Happy days are here again!
 
I was doing great last night with the kit until just after midnight I
discovered this audio problem.  Right after that I looked over to my
computer screen and my system had crashed.  I was beginning to wonder what I
did to cause all this to happen?  Windows XP is usually very stable.  I'm
running a beta version of Microsoft's Antispyware and it had just run and
gave me some real bad sounding error messages.  The system wouldn't reboot.
It said the kernel was missing.  Not only that file but the whole system32
directory was gone!  By this time I wasn't too happy.  The good news is I'm
using Norton Ghost and my system gets backed up every 3 hours to my D drive.
I was able to rebuild my complete system in about 1 hour (this morning).
I've been using Ghost for a few years and have found it to be a great
program.  You just have to boot from a supplied CD and restore from an
image.  The restored system comes up without any errors.  I've use many much
more expensive backup schemes at work and this beats them all, hands down,
in my opinion.
So now as I've said, all is well in the world again.  At least for me.
 
Thanks again.  I hope this helps others if they have this problem too.
 
Roger, W1EM

-----Original Message-----
From: [hidden email] [mailto:[hidden email]]
Sent: Monday, September 19, 2005 2:44 PM
To: [hidden email]
Subject: Re: [Elecraft] Chirp/Raspy problem with new K2 #5116



Hi Roger,
 
Check RFC15 the supply feed to the PLL chip U4 pin 16 on the K2 RF Board.
Usually caused by this going open circuit and needs to be checked with an
ohmeter. If O/C can be temporarily be shorted out until a new RFC15 is
obtained from Elecraft.
 
Regards,
Bob, G3VVT
K2 #4168

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