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. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
