[RFI] RFI from Astron power supply

[Bryan Swadener]

In the late 80s, I worked for 4 years at a 2-way radio
retailer (Amateur, Business & CB).  We handled the
complete line of Astron supplies, and in that 4 years,
I seldom saw one of their products returned as
defective.  Their linear supplies are a classic
design, based on the venerable '723.  Of the few
failures we did see, there were a couple of dead 723s,
a shorted bridge rectifier, and one shorted pass
(TO-3) transistor.  My personal experience is with an
RS20A I bought while employed there.  It has been
continuously energized since then and has been seen
close to full load often -- zero issues.  That's my
$0.02 worth.

73,
Bryan WA7PRC

--- Jim P wrote:
> 
> I have to beg to differ that this series of Astrons
> (the
> linears like the RS-35M et al) are all that
> 'reliable'.
> 
> I have had to replace the LM723 (I think it is)
> regulator
> on a couple of these and have since made a circuit
> change (added a resistor) to give the regulator a
> better
> chance at life.
> 
> The 'symptom' of failure was the inability to
> deliver rated
> current without voltage 'sag'.
> 
> It is also a good idea to add an LED (with suitable
> series
> resistor) across the unregulated DC side of the
> transformer
> and make this visible/viewable through one of the
> slots on
> the top of the supply towards the rear.
> 
> This does two things: you will know when you 'lose'
> the
> regulator side of the PS but know you have unreg DC
> and
> this also provides a bleed-off path. My recollection
> is that
> there isn't a suitable bleed-off on that series
> (maybe the
> earlier ones anyway which may be what I have.)
> 
> Jim P  // WB5WPA //


       
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