[NJARC] Selenium Rectifier replacement

[William Zukowski]

I replaced a selenium rectifier in a TO with a 1N4007 and had to increase the series resistor from 20 ohms to 47.  The series filaments are fed from the rectified DC, and the 1 volt tubes needed the additional resistance get them to the normal 1.3 volts.  So yes the resistor is necessary.

Sent from my iPhone

> On Apr 15, 2016, at 17:38, Sal Brisindi via NJARC <njarc at mailman.qth.net> wrote:
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> You should put a resistor in series with the silicon diode as the B+ will be higher when replacing the selenium diode.
> 
> Sal
> From: Matt Reynolds
> Sent: ‎4/‎15/‎2016 5:10 PM
> To: NJARC Reflector
> Subject: Re: [NJARC] Selenium Rectifier replacement
> 
> Just remember
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> Reply All = Everyone
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> 
>    I'm probably the least knowledgeable\qualified person on this thread thus far when it comes to radio repair but I was always under the impression the resistor was added to the diode to help account for the differences in how the selenium rectifier works\"acts" in relation to the silicon diode replacement.  It was my understanding the resistor was not added to protect the diode, but the resistor was to protect "the radio" from being "harmed" by the different characteristics of the silicon replacement.  I don't ever think I've heard of fear of the modern part being damaged/burnt out.
> 
> Matt
> 
> ________________________________________
> From: NJARC <njarc-bounces at mailman.qth.net> on behalf of Raymond F Chase <raydio862 at verizon.net>
> Sent: Friday, April 15, 2016 4:35 PM
> To: 'David Sica'; 'Jim Whartenby'; njarc at mailman.qth.net
> Subject: Re: [NJARC] Selenium Rectifier replacement
> 
> Just remember
> Reply = Poster
> Reply All = Everyone
> 
> _________________________________________________________
> The predominant failure modes for silicon diodes are: 1. Overheating the
> junction by gross current overloads and 2: Exceeding the peak inverse
> voltage (PIV) rating.  Silicon diodes with 10 times the expected current
> rating and several times the PIV cost pennies so they will be the last to
> fail.
> Ray
> 
> -----Original Message-----
> From: NJARC [mailto:njarc-bounces at mailman.qth.net] On Behalf Of David Sica
> Sent: Friday, April 15, 2016 4:03 PM
> To: Jim Whartenby <antqradio at sbcglobal.net>; njarc at mailman.qth.net
> Subject: Re: [NJARC] Selenium Rectifier replacement
> 
> Just remember
> Reply = Poster
> Reply All = Everyone
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