Is the key line indication on all the time? This may be indicative of a stuck key line. There was an unsoldered resistor on mine causing the issue.
73, Mark W7MLG On Sun, Apr 18, 2021, 2:38 PM <ws6x....@gmail.com> wrote: > I just purchased a used KPA500 (SN 0456) from a close friend. The amp was > just back to the factory for several repairs and was thoroughly tested. The > report reads, "KPA500 #0456 meets or exceeds all factory specifications." > My > friend unboxed the amp and made several QSOs to be sure all issues were > fixed. He then personally delivered the amp to my QTH. > Over the weekend I got the amp added to my operating position and was quite > surprised to find that input signals are attenuated significantly when the > amp is switched from STBY to OPER. No, this is NOT the issue with having > the > aux cable and the PA key line connected at the same time. This is with NO > PA > key, and NO aux cable connected. The amp has no connection but RF input and > output. It is independent of band. This is with a matched antenna, band > switched manually with the front panel buttons. When I engage OPER the > input > signal is attenuated by ~20 dB. > On the TX side, the amp is fine. On most bands I get full rated output into > a dummy load with approx. 20 Watts of drive from the K3. > I noticed on the service report, one of the tests was, "Tested receive > attenuation and IMD." I'm curious about "receive attenuation." This would > seem to be related to my problem. Looking at the block diagram, I surmise > something in the TR switch is malfunctioning. > Before I bug an already-overloaded Elecraft support, I am open to > suggestions. Am I missing something obvious? > TIA es 73, > Jim - WS6X > P.S. Yes, I have read the manual, and scoured the archives. The only thing > I > can find regarding input attenuation in the OPER mode involves incorrect > cabling. > > ______________________________________________________________ > 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 marklgoldb...@gmail.com > ______________________________________________________________ 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
