New K3 Line Out problem: FIXED!

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New K3 Line Out problem: FIXED!

Neoklis Kyriazis
Phew! How lucky can you get...

My original problem on my new K3 was that there was no output form the Line Out
socket and very low sensitivity to input signal at the Line In socket. I now know that
another problem I had was that with CONFIG SPKR+PH NO, the speaker would go
silent after a couple of seconds, even with no phones plugged in anywhere.

I tried to trace the Line Out circuit, starting from the DSP's output. I had to remove
the front half of the bottom cover to access P50, where the AF interconnections to
the DSP are grouped. I found no output on Pin 10 of P50 where the Line Out signal
is delivered by the DSP.

While wondering what may be wrong, I noticed that the DSP board was not lying

parallel to the front panel so I suspected it wasn't mounted right. I removed the

left side panel and I then realized that I plugged J50 into P50 with the top row of
pins into the botton row of sockets, so that half the pins where not connected!
I fixed the problem and re-assembled the K3 and voila! all was well with the faults
mentioned above.

However my troubles were not over just yet... I noticed that in CW mode and listening
to our local beacon on 50.499, there was a lot of distortion that sounded like clipping
of the audio output. On AM and listening to a local station the audio sounded good.
I really couldn't figure out why but eventually the fault cleared by itself, with the

distortion going away slowly! Don't know what was wrong (possibly an electrolytic?)
but I sure am very thankful it did....

I guess I should also be thankful that my sloppy assembling of the front panel didn't
cause any permanent damage, possibly because there is no DC involved and the pin
connections are mostly symmetric (Lineout-Left - Lineout Right etc).

One nice point that came out of this experience is that I was right about one

thing - one strong motive to buy a K3 kit was user repairability. I had an FT847 that
developed a fault on the RIT control but I could find no spares, even from the makers,
and I damaged it further trying to access the front panel internals. Kits for ever! ;-)

Also, one advantage of modern times - I used the schematics and assembly manuals
that are available on Elecraft's website in PDF format. Tracing a signal by name (like
LINEOUT_R etc) was so much easier than searching in paper schematics - I used the
keyword search of the PDF reader and could navigate the schematics with the click
of a button!

Thanks Elecraft, and all responders.


 
Regards

Neoklis - Ham Radio Call 5B4AZ
QTH Locator KM64KR
Website: http://www.qsl.net/5b4az/
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