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Re: [RFI] RFI from Astron power supply

To: "Jim Miller" <JimMiller@STL-OnLine.Net>
Subject: Re: [RFI] RFI from Astron power supply
From: "Jim P" <jvpoll@dallas.net>
Date: Mon, 28 May 2007 15:02:57 -0500
List-post: <mailto:rfi@contesting.com>
Jim M -

I threw some stuff down about the Astron mods on
a website at:


That's a good idea to place a spare 723 inside the
chassis; since that is really the only place I think I
use them around here I'm going to put one each
inside my 2 Astrons too. I'm also going to print
out a copy of the schematic and place that in
there folded up.

I got to thinking about the failure mechanism on those
Astrons; maybe the failure mode is not within the IC
itself (device failure) but perhaps it lies with the tin-lead
DIP leads and the socket on the PWB in the power
supply. Both my Astrons were picked up used and
one of them because it had 'failed'; one just had
a 'sag' in output voltage at only about 7 amps.

To that end I added some references to papers written
about contact issues on that web page too.

I've been using WD-40 as a poor man's contact
enhancer for years now, the PC I'm using right now
(a 500 MHz Pentium 3 with Win '98) has had it's
second application of WD-40 during a routine
maintainance dust suck-out a couple of years
back; no ill effects due to WD-40.

I applied WD-40 it to the Intel Slot 1 processor's
contacts, to all the RAM module contacts and all
PCI cards before insertion using a Q-tip.

I started this regimen on a 33 MHz 386 when I had
power supply connector issues (obvious heating/
discoloring of the contact pins) - and have used
WD-40 on all personal computer electrical contacts
since then. I also use it on RF contacts but I'll
save that dissertation for another time.

Jim P  //  WB5WPA  //

----- Original Message ----- 
From: "Jim Miller" <JimMiller@STL-OnLine.Net>
To: "Jim P" <jvpoll@dallas.net>
Cc: <rfi@contesting.com>
Sent: Saturday, May 26, 2007 8:09 PM
Subject: Re: [RFI] RFI from Astron power supply

> I would like to see a drawing or description of exactly where you placed
> resister and the value and where you connected the led.  Interesting.
> I lost one 723 chip in a RS20M but that was all.  I since bought 25 of
> ($25 minimum order) and some other stuff (the chips were something like 67
> cents each) because the only one I could get at the time was from Radio
> Shack for over $6 and I had to drive 80 miles round trip because I had to
> have it right away.  I was net control and had over 1500 bicycles arriving
> in the morning.  I now have a spare 723 chip inside each of my power
> supplies, RS70M, RS35M, and the RS20M (actually I just sold the RS20M).  I
> have never lost another and the only other problem I am aware of was
> on a shorted transformer but I really question the diagnosis and I never
> see it.
> 73, Jim

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