I seem to recall that from my R-390A/URRs. The transformer in the R-390/URR doesn't seem to do that. The cost reduction must have taken its toll there.
Thanks, Barry - N4BUQ On Sat, Oct 19, 2024 at 8:21 AM Tom Frobase <[email protected]> wrote: > > Some are noisier than others. I have a large supply here if you want to > replace it. Contact me offline ... tom, N3LLL > > On Sat, Oct 19, 2024 at 8:18 AM Leo Reynolds via R-390 < > [email protected]> wrote: > > > Is it normal for a R-390A power transformer to hum audibly? Not through > > the speaker, though there is a little there too, but through slight chassis > > vibration. It is there from the instant of turning on power and changes > > slightly as the rectifier starts conducting and B+ flows. It is easily > > audible in the shack, as if it were a small AM broadcast transmitter minus > > the blower. > > > > Thanks, > > > > Leo Reynolds > > K4LDR > > > > > > > > ______________________________________________________________ > > R-390 mailing list > > Home: http://mailman.qth.net/mailman/listinfo/r-390 > > 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 > > > ______________________________________________________________ > R-390 mailing list > Home: http://mailman.qth.net/mailman/listinfo/r-390 > 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 ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 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
