When my K2/100 is keyed in SSB mode (connected to a dummy load) and the microphone is gently tapped, I can hear a faint noise coming from somewhere on the KPA100 printed circuit board. It is a low level buzzing/rattling noise similar to a small metal object vibrating against a loudspeaker cone but I have disconnected the loudspeaker to eliminate this possibility.
It is only noticeable in high power mode (at levels above about 20 Watts) on 40 metres which points to relays K5 and K6 in the KPA low pass filter but as these relays are shared with the 30 metre band, I can't understand why the problem isn't present on 30 metres. I have tried applying pressure to magnetic components such as relays and toroids to try and locate the source of the noise and even used an insulated rod to try and mechanically couple the noise from suspected components into my ear but without success. I have not checked the solder side of the board for signs of damage but could the noise be arcing around the relay contacts? Apart from the noise, it seems to work perfectly giving 100+ Watts output on this band. Any suggestions greatfully received, Ray M1FJL -- View this message in context: http://elecraft.365791.n2.nabble.com/KPA100-Acoustic-Noise-tp7585970.html Sent from the Elecraft mailing list archive at Nabble.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
