New diodes arrived yesterday, thanks to Richard at Elecraft. After installation and re-calibration of the SWR/wattmeter, everything looks good, I made two quick contacts on 20m PSK31, one in Greece, the other in Slovak Republic.
Thanks again Don, Richard, and Elecraft! 73, David AJ4TF On Sat, 2011-06-11 at 19:48 -0400, david wrote: > Don, > > Thanks for confirming my diagnosis. I *usually* remember to disconnect > the antenna when I am not operating. > > I assume that the standard 1N5711 will work, Elecraft doesn't screen > them for any special characteristics do they? > > As always, I'm sure I'm not the only one that appreciates the knowledge > you bring to the Elecraft community. > > David AJ4TF > > > On Sat, 2011-06-11 at 18:13 -0400, Don Wilhelm wrote: > > David, > > > > Yes, it looks like U5, U6, Q10, Q11 and the associated components are > > behaving as they should. > > > > It certainly could be that D16 and D17 are not either open or shorted, > > but are not fully functioning as they should. The fact that you could > > only get the resistance measured at the wiper of R26 as high as 30k does > > confirm that -- replace the diodes. > > > > It also seems from your description that things are a bit intermittent > > and erratic, so while you are in there to replace the diodes, give the > > soldering in the wattmeter area (particularly T4) a good inspection and > > perhaps re-flow the solder with a hot iron (800 degF for the KPA100 > > board), and perhaps add a tiny bit of new solder (actually you are > > adding a bit of flux). > > > > Yes, those diodes are sensitive to lightning surges. Switch the K2 > > antenna to a dummy load when not in use for best results. > > > > 73, > > Don W3FPR > > > > On 6/11/2011 4:42 PM, david wrote: > > > K2/100 s/n 7006 > > > Initial symptom: No control of output power at any knob setting. At > > > 1-9W setting, output was>10W as measured by external wattmeter, SWR > > > read back>9.9 (external meter shows around 1:1). At 10-100W setting, > > > output>100W, SWR>9.9. HI REFL message displayed. > > > > > > Unit was previously working fine for several months. > > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
