[Elecraft] OT: Repairing Astron RS-20

[Tom Hammond]

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: Elecraft at mailman.qth.net
>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