Hello John, That 'clicking' could very well be arcing -- as another reader has suggested. I have an AL-811H that has since been replaced by a KPA500 that also made a few clicking sounds that I recognized as arcing and though I shut it off immediately, the damage had been done. The tubes were fine, but several of the diodes in the HV power supply, most of the bleeder resistors as well as ALL of the filter capacitors were damaged. I suspect it was a chain-reaction caused by a single bleeder failure which allowed the voltage across other caps to become excessive, etc...
Fortunately, they are all easy to check and replace (capacitors held to a pc board via screw terminals), and the cost of the components from Ameritron/MFJ was very reasonable. After replacing them, the amp worked just fine again. Of course BE VERY CAREFUL when working on your amplifier, and assure that all capacitors have been fully discharged before doing ANY work on it. Best of luck w/ your troubleshooting. 73, Dale WA8SRA > Hi all, > This could be tangentially related to a K3 issue, or maybe K3 experts can > give some insight here. FYI, when I am not using the amp, I can get 100W > from my K3 with no problem. Please keep reading... > > I have been using my AL-811 (not new, but new to me) successfully at 500W > for the past few weeks. Recently (actually, the second time this has > happened), my fuses both blew and I replaced them. Since I replaced them, > behavior has not been typical. I can't get anything over 200W (most is in > the 175W range). I use a tuner after the amp, and I know that the antenna > is matched quite well to the amp, but my SWR meter on my rig (K3) is > showing a high value. > > When I tune up at 20-25W I can get about 100W out from the amp. When I > move > to 50-65W I get < 200W. And there is clicking. I can't tell if it's a > relay > or if it's something else. > > So, the main issues are > 1. High SWR from the rig to the amp (when the antenna is < 2:1 SWR to the > amp) > 2. Low power from the amp to the antenna > > Happy to provide other information if folks have ideas on where to look. > > Thanks. > -john W4PAH > ______________________________________________________________ > 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
