[Elecraft] K3: 'Line In' problems

[jreber at TheBlueZone.net]

Thanks for the input, everyone. This is a great group.
The problem ended up being a solder whisker on CN2, pins 7 and 8, on the
Audio I/O board. Pins 7 and 8 of CN2 are the bypass caps  for the line in
center and shield. This effectively made the line in jack a dead short.
A quick touch of solder wick followed by a reflow of pins 7 and 8 on CN2
fixed the problem. I'm sure glad Elecraft put the schematics on their
website; That made it very easy to get to the bottom of the problem.

Line in is working great now, along with everything else. I've ran the rig
on RTTY, PSK31, SSB, and CW, and everything is working great.

Thanks again for the input.

Jason AC7JW


>   Most Line Out signal levels from PC soundcards seem to have a little too
> much drive for the K3's Line In  You might want to consider a 5-10 dB
> attenuator to allow enough granularity in the level control out from the
> PC.  I had this problem and built up a little 8 dB Pi attenuator for a
> 600 ohm line.  Formulas for this can be found in the ARRL Handbook or at
> http://www.daycounter.com/Calculators/PI-T-Pad-Attenuator-Calculator.phtml.
>
> matt W6NIA
> K3 #24
>
>
> Apr 13, 2009 06:35:57 AM, don at w3fpr.com wrote:
> Jason,
>
> Since you can drive the K3 from the mic input, I am wondering if you
> have enough signal available to drive the K3 LINE IN at its expected
> level.
>
> Do you have an in-line attenuator in the cable you are using at the K3
> LINE IN?  Or are you using an interface box that has an internal
> attenuator?  If so, you may not be getting enough signal into the LINE
> IN jack.
>
> Try connecting the Line-out from the soundcard directly to the K3 LINE
> IN jack using a straight stereo cable.  The K3 does not need any
> interface box or in-line attenuator.
>
> 73,
> Don W3FPR
>
> Jason Reber wrote:
>> Greetings everyone;
>>
>> I just got the new K3 assembled, and I'm really enjoying it. However, I
>> have an issue with the "line in" not working, and I wonder if anyone
>> else has seen this with a recently purchased K3.
>> I'm trying to use the "line in" for PSK 31, but the input is not
>> working. I've read previous posts, so I've ensured that the MIC SEL is
>> set to Line In, and that the mic gain for Line In is is not at zero.
>> When I move the cable to the rear panel Mic Input, and set the MIC SEL
>> to rP.L, everything works fine.
>>
>> I've tried the released firmware from January, and the current beta
>> firmware, and neither helps. Is there anything else I might be missing?
>>
>> Thanks,
>>
>> Jason  AC7JW
>>
>>
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