RE: OT: Repairing Astron RS-20

[w9gb]

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[Tom Hammond-3]

Greg:

Wish I'd had these (first two) references back YEARS ago when I was first
learning about linear supplies.. would have made things a LOT easier.

These should be MUST HAVE links for all hams!

73,

Tom   N0SS


At 03:15 AM 12/14/04, you wrote:

>Harold,
>
>A couple of suggestions in repairing your Astron.
>You MUST discharge the large filter capacitor before removing or replacing
>the LM723 regulator IC (this is the part you will likely have to replace).
>
>The RS-20 uses 2N3055 pass transistors, but you can also use 2N3771 (which
>is what Astron has been using on newer units).  Test the pass transistors,
>IF you are replacing the LM723 (testing with a VOM is covered in the KBT
>web site - below)
>
>Excellent reference web site for understanding, troubleshooting and
>repairing linear power supplies
>http://www.kbt-dc-supplies.com/index.php
>
>Dave Metz, WA0AUQ's  article "What Inside Your Astron?"
>http://www.seits.org/features/pwrsup.htm
>
>This is a very easy repair, and it one of the Amateur technical basics
>(audio, power, antennas) that I teach new amateurs.
>
>Astron schematic diagrams
>http://www.repeater-builder.com/rbtip/astron-index.html
>
>Greg
>w9gb
>
> > Message: 11
> > Date: Mon, 13 Dec 2004 09:47:45 -0600
> > From: "James" N5TOG
> > Subject: [Elecraft] OT: Astron RS 20 schematic
> >
> > Would some one have a schematic for an Astron RS 20 power supply they
> could
> > email me or know were i can find it.
> > Sincerely Harold N5TOG  K2 1587
>_______________________________________________
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[Tom Althoff]

Ditto!

Great post Greg!

----- Original Message -----
From: "Tom Hammond" <[hidden email]>
To: "G. Beat" <[hidden email]>; <[hidden email]>
Sent: Tuesday, December 14, 2004 8:44 AM
Subject: RE: [Elecraft] OT: Repairing Astron RS-20

> Greg:
>
> Wish I'd had these (first two) references back YEARS ago when I was first
> learning about linear supplies.. would have made things a LOT easier.
>
> These should be MUST HAVE links for all hams!
>
> 73,
>
> Tom   N0SS
>
>
> At 03:15 AM 12/14/04, you wrote:
> >Harold,
> >
> >A couple of suggestions in repairing your Astron.
> >You MUST discharge the large filter capacitor before removing or

replacing
> >the LM723 regulator IC (this is the part you will likely have to
replace).
> >
> >The RS-20 uses 2N3055 pass transistors, but you can also use 2N3771
(which
> >is what Astron has been using on newer units).  Test the pass
transistors,

> >IF you are replacing the LM723 (testing with a VOM is covered in the KBT
> >web site - below)
> >
> >Excellent reference web site for understanding, troubleshooting and
> >repairing linear power supplies
> >http://www.kbt-dc-supplies.com/index.php
> >
> >Dave Metz, WA0AUQ's  article "What Inside Your Astron?"
> >http://www.seits.org/features/pwrsup.htm
> >
> >This is a very easy repair, and it one of the Amateur technical basics
> >(audio, power, antennas) that I teach new amateurs.
> >
> >Astron schematic diagrams
> >http://www.repeater-builder.com/rbtip/astron-index.html
> >
> >Greg
> >w9gb
> >
> > > Message: 11
> > > Date: Mon, 13 Dec 2004 09:47:45 -0600
> > > From: "James" N5TOG
> > > Subject: [Elecraft] OT: Astron RS 20 schematic
> > >
> > > Would some one have a schematic for an Astron RS 20 power supply they
> > could
> > > email me or know were i can find it.
> > > Sincerely Harold N5TOG  K2 1587
> >_______________________________________________
> >Elecraft mailing list
> >Post to: [hidden email]
> >You must be a subscriber to post to the list.
> >Subscriber Info (Addr. Change, sub, unsub etc.):
> >http://mailman.qth.net/mailman/listinfo/elecraft
> >
> >Help: http://mailman.qth.net/subscribers.htm
> >Elecraft web page: http://www.elecraft.com
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):

http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

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