I did the same, but also added chunks of Dynamat to the inside of the chassis. I got a small quantity of Dynamat as off-cuts from a local car stereo shop.
Eric KI7LTT On Fri, Sep 29, 2023 at 2:12 PM Steve Lawrence via Elecraft < elecraft@mailman.qth.net> wrote: > Astron RS-35M Hum (and probably other Astrons). > > I've found some posts in the archives related to this topic so perhaps a > bit OT but hopefully of general interest. > > My Astron RS35M developed a hum that increased with increased load. > Otherwise working OK but became annoyingly loud. > > My solution was to insert a round rubber pad at each of the four mounting > screws between the chassis and the transformer. > > 3/4" OD x 1/4" ID x 1/8 inch thick. > > https://www.amazon.com/dp/B0BJPF9QMZ > > The hum now is very low. Nothing that would otherwise stand out if I > weren't listening for it. And it does not change with load or increased > load. > > So the problem seems to be mechanical coupling between the transformer and > the chassis with the hum amplified when the cover is on the PS. Likely > varies with any given batch of transformers. My much older RS-35M exhibits > no hum at all even under load. > > 73 - Steve WB6RSE > > ______________________________________________________________ > 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 garn...@gmail.com > -- --Eric _________________________________________ Eric Garner ______________________________________________________________ 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
