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

[Jerry Moore]

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.   Remove screws from top Cover, Repeat step2 - Notice NO buzzing or
distortion, the speaker sounds are clear.

4.   Disconnect all power/cables except ground.

5.   Tap the covers, top, sides,  front back, bottom, Found tapping the rear
bottom results in a perceptible rattle. 

6.   Remove bottom covers and inspect, no discernable cause, tapping board
results in a perceptible rattle.

7.   Remove Fan assembly, PA-100 unit. Tapping results in perceptible
rattle. 

8.   Inspect KLPA3A board - There's a transformer core that's loose to the
board.

9.   Tapping the KPA3A board results in a perceptible rattle. 

10.                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.