[Elecraft] K3s Odd sound vibrations - Hypothesis, Steps, Conclusion, and Request.

[Jerry Moore]

I resent the original and added a step. I get the buzzing with the monitor
down low. Increasing the level allows me the ability to better isolate and
hear it.
If you remove the screws from the top cover and hold it in your hand there
is no buzzing or distortion at any monitor level, or volume level. The
harmonic distortion appears to be completely and easily resolvable but I
need an approved adhesive to use. I'm not messing up my nice radio without
support and approval from the manf. 

Jerry Moore
CDXA, INDEXA, SKCC, Fists
AE4PB, K3S - S.N. 010324
http://www.qrz.com/db/AE4PB
An Amateur is - Considerate, Loyal, Progressive, Friendly, Balanced, and
Patriotic.


-----Original Message-----
From: Nr4c [mailto:nr4c at widomaker.com] 
Sent: Tuesday, February 16, 2016 10:35 PM
To: Jerry Moore
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3s Odd sound vibrations - Hypothesis, Steps,
Conclusion, and Request.

Why on earth would you turn the TX MON up all the way?  My front door would
be buzzing with it that loud. 

Sent from my iPhone
...nr4c. bill


> On Feb 16, 2016, at 10:14 PM, Jerry Moore <jermo at carolinaheli.com> wrote:
> 
> Hi, I thought I had the sound issue licked with the loose case screws 
> but I still hear the buzz. I believe I found the issue and it's NOT 
> the speaker (well I don't believe based on my findings).
> 
> 
> 
> Hypothesis:
> 
> I strongly suspect loose transformer cores are the cause of the 
> buzzing that are especially louder at different harmonics.
> 
> 
> 
> Steps to reproduce and isolate the issue: 
> 
> 1.   CW mode, Test (so no TX), Monitor all the way up (60? I think from
> memory..Rig is disassembled atm..).
> 
> 2.   Send a string of code, you can hear the tones but a buzzing,
listening
> to received code results in the same buzzing distortion and appears 
> harmonic.
> 
> 3.   Disconnect all power/cables except ground.
> 
> 4.   Tap the covers, top, sides,  front back, bottom, Found tapping the
rear
> bottom results in a perceptible rattle. 
> 
> 5.   Remove bottom covers and inspect, no discernable cause, tapping board
> results in a perceptible rattle.
> 
> 6.   Remove Fan assembly, PA-100 unit. Tapping results in perceptible
> rattle. 
> 
> 7.   Inspect KLPA3A board - There's a transformer core that's loose to the
> board.
> 
> 8.   Tapping the KPA3A board results in a perceptible rattle. 
> 
> 9.   Inspect the KPA3a board  - it contains a transformer core that's
loose
> to the board.
> 
> 
> 
> Conclusion:
> 
> I believe that using a high temperature silicon or other adhesive 
> approved by Elecraft to secure the transformer cores to the circuit 
> boards will resolve the issue.
> 
> 
> 
> Request:
> 
> I'd like to have an Elecraft representative review my information and 
> make a determination as to its validity AND recommend an Elecraft 
> acceptable solution if they agree there's an issue.
> 
> 
> 
> Thanks in advance.
> 
> Jer
> 
> 
> 
> Jerry Moore
> 
> CDXA, INDEXA, SKCC, Fists
> 
> AE4PB, K3S - S.N. 010324
> 
> http://www.qrz.com/db/AE4PB
> 
> An Amateur is - Considerate, Loyal, Progressive, Friendly, Balanced, 
> and Patriotic.
> 
> 
> 
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