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Title: Diode strings in secondary of mod trans Post by: w5dud on August 06, 2007, 03:02:03 PM Hello picked up a Globe King that has been modified and discovered that in the modulation transformer secondary ,that both leads have a string of diodes in them , is this to take the place of the resistor that went between the secondary leads, thanks W5DUD
Title: Re: Diode strings in secondary of mod trans Post by: 2ZE on August 06, 2007, 03:31:49 PM Probably zener diode clipping arrangement. Can confirm by reading the numbers off the diodes, and cross referencing them. There should be a long string of zener's connected anode side to the modulated B+, and a shorter string of silicon diodes connected anode side to the unmodulated B+, and the two strings meeting cathode to cathode somewhere.
Title: Re: Diode strings in secondary of mod trans Post by: W1RKW on August 06, 2007, 03:33:05 PM maybe this?
http://www.amwindow.org/tech/htm/zenlimd.htm Title: Re: Diode strings in secondary of mod trans Post by: w5dud on August 06, 2007, 05:47:56 PM Thanks for the info , after looking at it , that is what has been done, Thanks W5DUD
Title: Re: Diode strings in secondary of mod trans Post by: flintstone mop on August 06, 2007, 08:13:28 PM You might want to try cutting them out and listening to the TX audio. I bet it sounds better. I HAD a DX100 and it didn't like that diode limiting thing on the secondary. You can run some processed station audio into the input of the Tx or just use a good ole D-104 and that should give you plenty of audio. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
The iron in those Globe Kings wasn't the best. Consumer quality equipment. Not meant for 24/7 operation or lotta overloads. Fred |