Just remember that when you put the meter in the cathode circuit it measured combined plate & screen current.
Bob Macklin K5MYJ/7 Seattle, Wa. "REAL RADIOS GLOW IN THE DARK" ----- Original Message ----- From: "David Knepper" <[EMAIL PROTECTED]> To: "Discussion of AM Radio" <amradio@mailman.qth.net> Sent: Saturday, January 01, 2005 10:11 PM Subject: Re: [AMRadio] You Won't Believe This > John, thank you for this. > > Collins engineers did not adhere to safe operating practice when they placed > the 800 ma meter in the positive lead going to the R.F. choke. It should > have been in the negative lead as you suggested. > > > Dave, W3ST > Publisher of the Collins Journal > Secretary to the Collins Radio Association > www.collinsra.com > Nets: 3805 Khz, Monday/Wednesdays 8 PM EDST > 14250 Khz Saturday, 12 Noon EDST > > ----- Original Message ----- > From: "John Coleman, ARS WA5BXO" <[EMAIL PROTECTED]> > To: "'Discussion of AM Radio'" <amradio@mailman.qth.net> > Sent: Sunday, January 02, 2005 12:31 AM > Subject: RE: [AMRadio] You Won't Believe This > > > > I gather from the text about the HV meter and current meter that the > > current meter is above ground by 4000 Volts. I know that there are a > > lot of special mounting devices and hardware for this purpose but I > > still feel that it is a bad idea. I have always made sure that HV > > current metering was done in the current path that is close to ground > > potential. As a further precaution it is a good idea to put a 50 Volt > > or less avalanche diode across the meter in case it should become open. > > As for the defection phenomenon, it might even be possible that the > > continued HV on the meter has put permanent static charge in the > > molecular structure of the plastic. If this is the case then any > > connection even a ground on the meter would cause a deflection. In any > > case I would move the current metering circuit to the cathode circuit or > > the negative return of the power supply. Modification of initial > > circuitry sometimes requires lifting all the ground connections of > > filters and/or chokes to get a floating ground and then passing that > > through the meter for current readings. I my opinion it is well worth > > the effort. I always put chokes in the negative lead of power supplies > > as well. > > > > It is an interesting phenomenon though. So please let us know what you > > do find as the cause. > > > > 73, John, WA5BXO > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of David Knepper > > Sent: Saturday, January 01, 2005 5:31 PM > > To: Discussion of AM Radio; Collins Mail List > > > > Subject: [AMRadio] You Won't Believe This > > > > That is right, only one lead connected and the meter is reading negative > > current. I switched this lead to the negative post and the meter still > > deflects downward past zero. > > > > > > > > ______________________________________________________________ > > AMRadio mailing list > > Home: http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:AMRadio@mailman.qth.net > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net >
