They are going to want to know what is going on with the input power. The burned resistor (twice!) is a very good indication that there is indeed too much power flowing into the KPA’s front end at times. It is quite possible for any transmitter to put out more power than spec at times, especially if it is not properly calibrated. There are many rigs that as-designed have a bad tendency to overshoot drastically on key-down, then settle to the power they are supposed to be putting out. An analog wattmeter will not be fast enough to show the problem, but the amplifier’s input definitely sees it.
You need to get them to fix the KPA’s input circuit, but you should also investigate your transceiver to find out why it is overshooting at times. Perhaps it is in need of a fresh calibration or something else might be going on. 73! Jack, W6FB > On Apr 27, 2019, at 4:20 PM, Dave <rocke...@gmail.com> wrote: > > I can wait until tomorrow. Won’t bother them on Sunday. > > The symptom this time is different than last. Last time was amp acting like > tuner not tuned. This time showing excessive input power even though actual > power is fine. > > Let’s see what happens. > > Dave wo2x > > Sent from my waxed string and tin cans. > >> On Apr 27, 2019, at 7:17 PM, Don Wilhelm <donw...@embarqmail.com> wrote: >> >> Dave, >> >> Time to contact supp...@elecraft.com. >> Unfortunately, they are only open for the next 45 minutes (unless someone is >> working late), so be patient while the support folks enjoy their weekend. >> >> 73, >> Don W3FPR >> >>> On 4/27/2019 6:48 PM, rocke...@gmail.com wrote: >>> The input too high only happens into a non-resonant load (tuner in circuit). >>> Also noticed on 20 now when tuner is in operate there is a 3 dB drop in >>> noise floor. >>> This is the second time the 3 watt resistor has desoldered itself from the >>> board and both times the resistor is discolored. >>> Only one RF path from radios through switching into amp input. Amp output >>> feeds a 1x4 antenna switch. No other radios transmitting in near proximity. >>> Definitely something failed on filter board. >>> Dave wo2x >>> -----Original Message----- >>> From: Paul Baldock <p...@paulbaldock.com> >>> Sent: Saturday, April 27, 2019 6:21 PM >>> To: rocke...@gmail.com; elecraft@mailman.qth.net >>> Subject: Re: [Elecraft] KPA-1500 input too high >>> Try it in to a dummy load. >>> - Paul >>> At 02:48 PM 4/27/2019, rocke...@gmail.com wrote: >>>> Hi All, >>>> >>>> >>>> >>>> KPA-1500 s/n 423 >>>> >>>> >>>> >>>> Operating 80 meter SSB running 20 watts drive with tuner engaged for >>>> about >>>> 1240 watts out PEP. Remote app shows maximum power handling of 1620 watts. >>>> >>>> Out of nowhere I got an input power too high alarm @ 191 watts! The >>>> radio is capable of 100 watts out max and verified is set to 20 watts. >>>> >>>> >>>> >>>> Set tune power to 10 watts. >>>> >>>> Meter in amp during standby reads 10 watts. >>>> >>>> Switch to operate and immediately get input power too high alarm @ 91 >>> watts. >>>> >>>> >>>> >>>> Switch to 20 meters (resonant antenna). No issue - 10 watts tune is >>>> approximately 400 watts out with no error. >>>> >>>> >>>> >>>> Any ideas? >>>> >>>> >>>> >>>> Dave wo2x >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> ______________________________________________________________ >>>> 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 >>> ______________________________________________________________ >>> 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 > ______________________________________________________________ > 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 ______________________________________________________________ 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
