[Elecraft] Seeking Help Solving KAF2 Problem

[Dohn]

This is a post I used and then archived and may help you.

Your sidetone source likely was switched for some reason or other - maybe by
an 'extra' finger press while in the menu

Go back into the menu and dial up ST L, press EDIT to move the cursor over
to the right side and then tap DISPLAY to toggle the sidetone source.  When
you hear the sidetone, stop and exit from the menu.

In some rare instances, it may take a few 'toggles' to get things to switch
properly, so try it several times.  If you have a post SN 3000 K2 (or have
put the sidetone source change on an older K2 because you added the KPA100
or KIO2) your sidetone source should be 'U8 - 4' - you will see the source
displayed briefly each time it is toggled.

73,
Don W3FPR

Dohn   N8EWY

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dennis Payton
Sent: Thursday, March 01, 2007 10:19 PM
To: elecraft at mailman.qth.net
Subject: [Elecraft] Seeking Help Solving KAF2 Problem

A couple weeks ago, I got out my K2 and operated the ARRL International DX 
Contest. During the contest, my audio output was so low I had to constantly 
use the preamp just to hear on my headphones, so afterwards I opened the rig

up and tracked the problem down to the audio filter. Shorting pins 1 & 2 of 
J1 & J2 gave me full audio with the board removed, and flipping the 
board-mounted switch to "out" gave me full audio with the board installed.



That told me the problem 'had' to be in the filter board, but after checking

the DC voltages from the chart and thoroughly examining each component's 
location and solder joints, I found nothing. I decided to use a RS 
speaker-amp to follow the audio signal through the filter to see where it 
was getting attenuated, but was very surprised to not see it getting 
attenuated anywhere. The filter appears to work properly from beginning to 
end. The audio at pins 1 & 2 of J1 & J2 all sound fine to me, whether the 
filter is switched in or out, but the K2's audio is 'greatly' attenuated 
when the filter is switched in. Although I'd made sure the filters were 
aligned with each other when I first started troubleshooting, I thought that

was all that was left, so I started checking them again. Then, at one point,

I hit the "spot" button and discovered I suddenly had no sidetone. I spent 
quite a bit of time trying to figure out what happened, but couldn't get any

power from pin 25 of the MCU whether I keyed the rig, hit "spot", or turned 
the rig off & on. Then as a curiosity after giving up, I removed the audio 
filter board. That gave me sidetone again! Next, I reinstalled the board and

I still had sidetone, so something must have "locked up"? Now, I've got the 
filter removed again though, and have decided that I'm at the end of my 
ability.



Something else I think I should mention is that I measure 5.15 volts on pins

1 & 2 of  J1 on the control board. I hope that's expected. Also, I don't 
know if I've had this problem since the beginning or if it just popped up. I

haven't operated the K2 since installing the KAF2 quite some time ago, and I

just don't remember how I left it.



Any advice would sure be appreciated.



Thanks!



Denny Payton    N9JXY



(By the way, I worked Auckland, New Zealand on 40-meters during the contest 
operating one watt. That calculated to be 8312 miles-per-watt, which is by 
far a new record for me. My antenna is just an R7 vertical mounted on a shed

in my back yard.)


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