Re: {Collins} 516F-2 power supply hum when off



Group,

Will the inrush current limiter sold by Electric Radio protect this switch, or is the damage done when switching OFF?  The inrush limiter lengthens tube life, and slightly reduces line voltage back to where it belongs, so it seems like a good idea.  This would be one more benefit.

Steve, WA6UAT

-----Original Message-----
From: collins-bounces@xxxxxxxxxxxxx [mailto:collins-bounces@xxxxxxxxxxxxx] On Behalf Of W9HAK
Sent: Sunday, May 31, 2009 3:24 AM
To: donroden@xxxxxxxxxx
Cc: collins@xxxxxxxxxxxxx
Subject: Re: {Collins} 516F-2 power supply hum when off

donroden@xxxxxxxxxx wrote:
> I'd love to see a schematic of that if it's available.
>
> Don WA4NPL
>
>
> Quoting entropycat@xxxxxxxxxxx:
>
>> Greetings to Jim and the list:
>>
>>    My first guess is that your supply has been modified to include a low
>> voltage low current control supply for a relay to switch the actual 
>> AC to
>> the 516F2 transformer.   This is often done (I've made such a mod 
>> myself in
>> my 516F2) to reduce the load on the on-off switch in the 32S- and KWM-2
>> radios.   These switches are made out of unobtanium, and reducing the
>> voltage and current they have to switch is a good idea.
>>
>>    Just my $.02 worth.
>>
>> 73,
>> Jim T.
>> KB6GM
>> entropycat@xxxxxxxxxxx
>> "entropycat" copyright 2008 James K. Thorusen
>> All Rights Reserved
>>
>> ----- Original Message -----
>> From: Jim Hendershot
>> To: collins@xxxxxxxxxxxxx
>> Sent: Saturday, May 30, 2009 17:06
>> Subject: {Collins} 516F-2 power supply hum when off
>>
>>
>> Hello to the group!  Sorry I missed the banquet at Dayton.  I got
>> waylaid!  Glad to hear it went so well, I was bummed to miss it.
>>
>> I have a curious thing happening with my 516F-2 power supply.  It is a
>> winged emblem unit, and when it is off, it still produces a small AC
>> power line related hum.
>>
>> I've looked at the schematic, and cannot figure out what this is.
>> When I turn the rig on, the main transformer kicks in, and the hum is
>> clearly different, and more what I would expect from a running
>> supply.  The hum when the rig is off, however, is quite small, but
>> definitely there.  Kind of the level one would expect from a small
>> filament transformer.
>>
>> Nothing appears to be running when the supply is off.  No lights,
>> filaments, etc.  Also, when I unplug the supply, the small hum
>> definitely quits, so something is happening, that's for sure!
>>
>> Before I open the supply to hunt this down, perhaps someone could
>> inform me of something I'm missing, in order to put my mind at ease.
>> Any ideas?  Thanks!
>>
>> 73,
>> Jim
>>
>> _______________________________________________
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>>
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>>
>
> _______________________________________________
> SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
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>
>
> NETS: Tues & Thur: 3.805 MHz-2000 Central + Fri: 3.895 MHz-2000 Pacific
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> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
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> Version: 8.5.339 / Virus Database: 270.12.46/2144 - Release Date: 05/30/09 17:53:00
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>   
This link will take you to that information. Look at the bottom of the 
page for the link to the original article.

http://www.collinsra.com/cra_album/0507_09/0507_09.html

Smith Bradford
W9HAK

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SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
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  SUNDAYS: 14.263 MHz-2000 UTC  +  AM Net: 29.050 MHz-1200 Central
  1st Wednesday AM Net 3.880 MHz-2000 local (ET, CT, MT, PT)









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