Douglas, Perhaps the issue described in this elecraft thread describes your issue and provides an answer:
http://www.nabble.com/K2-100-kaputt-to14081805.html#a14081805 Good Luck, Robie - AJ4F On Sat, Feb 23, 2008 at 7:01 AM, Douglas Maxwell <[EMAIL PROTECTED]> wrote: > Hi All, > My K2 is serial no. 4688. I have just purchased and built the latest spec > KPA100 unit for it. The manual for the KPA100 suggests modifications are > required for K2's with serial nos 4059 or lower. As my serial number is > higher, I assumed all would be well. Firstly the KPA100 performs well on all > bands using CW mode. Recently I tried SSB and found that the PA is going into > oscillation when on 40m. > > Setting the power out to 20W and speaking into the microphone produces 100W > output peaks accompanied with a low buzzing sound in the speaker on audio > peaks. Varying the power control brings it back into line only to start > misbehaving again after a few more words are spoken or if the mode is cycled > back round to LSB or you switch off then on again. This happens when > connected to a dummy load with no other connections other than the mike and > power supply. I changed out the power supply, but the same problem exists. > > I have done an extensive search of the internet to try and find solutions: > 1) I have ensured gnd continuity from the KPA100 to every part of the K2 > chassis. > 2) I covered the hole in the shield near the pl259 with copper tape and > ensured gnd continuity. > 3) I saw the article about installing the 270 ohm metal film resistor to > increase Zin, but my K2 circuit is newer than the authors and I haven't seen > an updated version. > 4) I have ensured the 2 lugs from the antenna socket to the shield are good. > 5) I have removed the KPA100 from the K2 entirely and the same problem exists. > > Does anyone know the solution or recognise these symptoms? > > Douglas Maxwell > GM0ELP > > > > > > _______________________________________________ > Elecraft mailing list > Post to: Elecraft@mailman.qth.net > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
