I talked to Peter on the phone. He has no bias current when amp is transmitting with no power applied (key on SSB without talking. He is reading 54 volts and has tried power cycling amp from power supply switch and reseated all cables. Definitely BAD distortion on SSB (we are close enough to hear each other). Looks like one RF device let loose and it is dragging down the bias voltage. That is my guess.
Dave wo2x -----Original Message----- From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On Behalf Of Wes Sent: Saturday, February 16, 2019 9:49 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA-1500 failed! I think a two-tone test is the best evaluation tool.. The generator is built into the K3 if you have another receiver that you can use to listen to the amp output. I use an SDR-IQ which is a very nice tool for this but any other SDR would do. Sorry for your pain. Wes N7WS On 2/16/2019 7:28 AM, li...@w2irt.net wrote: > I was operating in the ARRL-CW contest this morning and on 20m, with a > 1.2:1 SWR on the Yagi, all of a sudden I saw my power drop to about > 450-500W with about 40W in. Worked a few stations but not as easily as > when I turned everything on this morning. Switched over to phone and made a > few contacts. > Audio is fine barefoot with 100W out of the K3s-which suffered blown > finals itself during CQWW SSB last fall, but with the amp in I got > reports that my audio was badly distorted. > > Before I send it in, is there anything I should look at or any > diagnostics I can easily perform? For the cost of this, I'd have > thought protection would have kicked in to prevent anything untoward > from happening. I'm in complete disbelief, to be honest. > > --------------------------------------------- > 73 and Good DX > Peter, W2IRT > ______________________________________________________________ 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 rocke...@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
