Is there an ATU involved? If so , the TX signal and RX signal are then common to the path through the ATU.
I don't think the RX signal goes through the 100W PA. Also consider the antenna port switching. That is common to both RX and TX signal paths. Bob, K4TAX Sent from my iPhone > On Aug 1, 2019, at 10:18 AM, Joe DeVincentis <j...@ko8v.net> wrote: > > Could it be overheating? Or is the temperature calibration is out of whack. > > Joe, > KO8V > >> On Aug 1, 2019, at 10:16, Richard Hoffman, K1DJ via Elecraft >> <elecraft@mailman.qth.net> wrote: >> >> Rig: K3S (100W with internal ATU), s/n 11064, P3, KPA500, KAT500, into >> SteppIR 3-el with 30/40 loop or wire dipoles/inverted-V's. >> >> Problem: My K3S 100 watt internal amplifier unit (K3S/100) has become >> intermittent. >> >> It first happened yesterday while I was running 100W on FT-8. [I have done >> this hundreds of times, sometimes for lengthy periods, over the past 18 >> months with no problems.] >> Suddenly, my power output dropped to zero, and my received signals audio and >> P3 display also suddenly went quiet. >> >> After some fiddling around, I figured out that if I reduced the K3S power to >> 10-12 watts, both transmit and receive came on again — leading me to >> conclude that it must be my 100W amp unit that had dropped out. >> >> I rebooted the rig and the 100W internal amp unit kicked back on. So I was >> hoping I had just triggered a protective circuit which had reset. The rig >> worked fine at 100W for a subsequent hour-long multi-band CWOPs CWT CW >> session at 100W. Then, however, a few minutes into the next CWT session >> hours later, the same thing happened again. Power output suddenly dropped >> from 100W to 0, and received audio and a P-3 screen filled with many medium >> to strong CWOPs signals simultaneously went quiet. >> >> I reduced the power on the K3S down to 10W, and both transmit and receive >> worked again, but only at low power. >> Please pass along any helpful suggestions, and thanks! >> Richard Hoffman (Rich), K1DJScituate, MA > > ______________________________________________________________ > 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 rmcg...@blomand.net ______________________________________________________________ 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
