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

[Nr4c]

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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