[R-390] R-390A and the Selenium Rectifier
Glen Galati
[email protected]
Fri, 7 Nov 2003 01:48:28 -0800
Hello Barry,
I think you still got Sel rect poisoning. I know I do, the taste is still
in my mouth. I say OM, "if it's working-leave it be". Check voltage or front
to back resistance, and if its better than 10:1, leave it in. I've only
worked on ten or so 390A's in my Air Force career, and never seen one go
south. Of course that was 20-40 years ago, and a lot of signals have passed
the airwaves in that time. I think the real experts should step forward at
this time and relay their thoughts on the subject.
73,
Glen Galati KA7BOJ
Tacoma, WA
[email protected]
----- Original Message -----
From: "Barry Hauser" <[email protected]>
To: "John KA1XC" <[email protected]>; "R-390 reflector"
<[email protected]>
Sent: Thursday, November 06, 2003 8:14 PM
Subject: Re: [R-390] R-390A and the Selenium Rectifier
> Hi John
>
> Generally a good idea to replace all seleniums with silicon as a
preventive
> maintenance. I'm not exactly on schedule in that department -- lot's of
> radios of various kinds with seleniums and even some copper oxide ones.
>
> The cosmetically correct thing to "rectify" the situation is to bypass
them,
> leave them in place and install the silicon rectifiers or bridge next to
the
> original.
>
> I haven't had a selenium fail lately -- last one I remember was when I was
> about 12 years old and the Se rectifier went in the little Motorola TV (a
> '47 model, I think). Boy did that stink to high heck! Very pungent.
Lot's
> of smoke. I still can smell it more than 4 decades later. Not sure what
> the power rating was for that square-finned wonder - maybe about 5
> deadhorsepower or maybe 3-skunkpower. My uncle knew immediately what it
was
> that blew and replaced it with the latest technology -- one of those
> shiny-tiny top hat rectifiers -- I guess it was half-wave -- not sure. I
> was amazed how small it was.
>
> Barry
>
>
>
>
> ----- Original Message -----
> From: "John KA1XC" <[email protected]>
> To: "R-390 reflector" <[email protected]>
> Sent: Thursday, November 06, 2003 10:41 PM
> Subject: [R-390] R-390A and the Selenium Rectifier
>
>
> > I'd like to get some wisdom regarding the selenium rectifier used to
make
> > the DC for the relays.
> >
> > I've got an Imperial (really mostly Teledyne) radio of about 1963
vintage,
> > and the selenium rectifier seems to be working fine. However, I'm doing
a
> > top to bottom refurb (recap etc) on this radio for a friend and I'm
> > wondering if this might be a likely failure down the road and would be
> worth
> > replacing with a silicon bridge.
> >
> > If this was an R-390 it would be an easy decision as the copper oxide
> > rectifier stack is always toast!
> >
> > thanks,
> > John
> >
> >
> > _______________________________________________
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> > http://mailman.qth.net/mailman/listinfo/r-390
>
>
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