On 4/7/2012 10:24 AM, Dave Van Wallaghen wrote: > I would be interested to see if I could > make the change myself.
I cleaned up a couple of cheap switchers that I bought at a hamfest by adding a line-voltage rated capacitor across the AC line, an RF cap across the DC output, and serious multi-turn ferrite chokes to both the AC line and the DC output. I also added a couple of clamp-on cores to kill the stuff on 2M. Total cost of my clean-up was about $10 (I bought the cores as part of a group purchase for $4 each), and the power supplies cost me $10 each. Doing it right when they built them would probably have added less than a buck to the cost, and most of doing it right is circuit layout, not components. See my RFI tutorial for guidelines on winding the chokes, and also for detailed info about line-voltage rated capacitors. Hint -- they must be rated for the surges of several kV that often occur on the AC line. 73, Jim K9YC ______________________________________________________________ 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
