Hi Declan, actually the line filters in switch-mode power supplies are meant to keep the noise inside the power supply rather than keeping something out. So just look inside a normal PC power supply...
OK it has to be a modern one, the old ones I found lying around here at home do not have any filtering... Uwe. > Recently, Somebody Somewhere wrote these words >> I'm not sure I understand your question but I think the answer to your >> question is option #1. That's because the circuit needs a low source >> (power supply) impedance. I suspect your RFI is caused by parasitic >> oscillations setup by the higher Ft of your replacement transistors. >> Again, guessing, your replaced the old steel case TO3s with aluminum >> case TO3s. One simple solution is to find some steel case BUX80s. If >> they are not available you might try killing the oscillations with 100 >> pF caps from collector to ground. You may need to increase Rb on the >> transistors too. >> >> Fred Townsend >> > I put in Manufacturer replacement (Aluminium) BUX 80s before testing. > My take on the thing is this: The earthing is poor, like so > (Anklebone connected to ..................... neck) > The inductive spikes are getting out through poor diodes, and the > transistors were a red herring. The machine was made to make noise, and > that's what it does. > So I was looking at constructing a mains filter to test this, and see if > that would solve it. >>Option 1: >>Mains-----Inductor----------------Bridge Rectifier >> Capacitor >>Mains-----Inductor----------------Bridge Rectifier >> >>Or some other way, e.g. >> >>Option 2: >>Mains----------------Inductor------Bridge Rectifier >> Capacitor >>Mains----------------Inductor------Bridge Rectifier >> >> >> >> > -- > With best Regards, > Declan Moriarty. -- Author: Uwe Zimmermann INET: [EMAIL PROTECTED] Fat City Hosting, San Diego, California -- http://www.fatcity.com --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
