Sounds like an intermittent bad connection?
You might check and see if there¡¯s any possibility of looseness on the BNC pin-to-socket connection.
After that, I would look very carefully at the source connection of the power MOSFETS. ??
Make sure there is a tiny convex mound of solder on the source lead, and that it is not dropping into the printed circuit board concave ; if it is dropping in, I would very carefully add a tiny bit more lead tin solder.?
I had this happen to me and the output doesn¡¯t completely go away, but it drops by about 20 DB. One of the two mosfets was no longer making a good source connection so it was not really a push pull anymore. ? If you have a sensitive output monitor of some sort, you might be able to see that. ?
A tiny bit of solder and it was fixed. I would tell you that I switched my insulators to aluminum nitride, but unless you are really pushing higher power, I don¡¯t think that¡¯s a problem. ?
And I would mention that my issues were with the 40 W V2 version, so it¡¯s not guaranteed this applies ?to the current version?
Gordon kx4z?
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On Nov 25, 2024, at 11:50, Andreas Zahmel DO6DOC via groups.io <andreas.zahmel@...> wrote:
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Here is some feedback,
in the last 3 weeks there was a lot of email traffic with the support of hfsignals. I have made several videos on request from the behavior of the
TRX to measurement setups to show in the video how the quiescent current is and what happens during transmission.
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Today I was told to desolder the MOSFETs by chance, you don't know exactly where the error could be and install the supplied ones myself because I contacted them 3 days after the warranty expired.
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The error was noticed for the first time 14 days after receiving the device, 1-2 times no transmission power at approx. 50 FT 8 QSOS in 4-5 days.
A week later I started up again and everything worked normally again, 4-5 days later the same error, out of 100 transmissions 2-3 times no power - of course I first redid the software,
opened the device at the weekend to look for faulty areas, reassembled everything and retested, the device then ran for about 1 week without problems and then the error
was there more often, at that point I turned to the forum here and at the same time to HFsignals
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and now I'm told because I got in touch 3 days too late it's not a warranty case, that's kind of frustrating so next time, as soon as even the smallest error occurs in our
experimental hobby, write to support immediately and never try to solve it yourself.
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Andy
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