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THE AM BULLETIN BOARD => Technical Forum => Topic started by: ve3cpo on March 03, 2013, 09:30:21 PM



Title: diodes
Post by: ve3cpo on March 03, 2013, 09:30:21 PM
Hi men I have a old Hallicrafters with a selenium rectifier how do I put in a modern diode?    Darryl   73   


Title: Re: diodes
Post by: KB2WIG on March 03, 2013, 09:35:18 PM
D,

Which Old Halli??

klc


Title: Re: diodes
Post by: W2VW on March 03, 2013, 09:40:02 PM
Tack modern diode in parallel with it. Lower voltage drop. Evil selenium diode disappears electrically.


Title: Re: diodes
Post by: wa3dsp on March 03, 2013, 10:22:08 PM
Tacking diodes across certainly works but to me it is the lazy way. I would take out the old rectifier which is usually mounted with a screw and nut and put in a terminal strip in its place and mounted the diode(s) on it. It is true that the old selenium rectifier should be passive with the silicon diode across it but you never know for sure so I would rsther not have it in there.


Title: Re: diodes
Post by: Steve - K4HX on March 03, 2013, 10:28:48 PM
But then it won't be STOCK!   ;D


Title: Re: diodes
Post by: KA2DZT on March 04, 2013, 03:05:07 AM
But then it won't be STOCK!   ;D

Rotten egg smell is also not stock.

Fred


Title: Re: diodes
Post by: K3ZS on March 04, 2013, 08:40:50 AM
Sometimes you need a series resistor to keep the voltage from going too high.  I blew out a filter cap after just replacing a selenium with a silicone diode in an old receiver.


Title: Re: diodes
Post by: ve3cpo on March 04, 2013, 04:49:03 PM
Thanks for the replys it is a old Halli 5r40 the first radio I ever had just got off Ebay  Brings back some memories from 50 yrs. ago   73  Darryl  ve3cpo
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