Silent power supply for a K3s

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Silent power supply for a K3s

Peter W2IRT
Hi all,
I would like to find a power supply to power the K3s that is completely
silent. I've owned an Astron RS-35M, which was great until it started
buzzing like crazy. I swapped that out for a Samlex SEC-1235M, and did the
fan mod to keep the fan on constantly at low speed. The problem here is that
when I'm running FT8 or RTTY for more than about a half hour, the fan goes
into high speed and stays there for an hour or more, long after the rig and
amp's fans have shut off. And because it's a tiny fan moving a lot of air,
it's incredibly loud.

I'm looking for an RF-clean power supply (either linear or switching) that
can deliver 25A continuously without requiring a cooling fan of any kind.
All it's running is the K3s/P3 and a couple of boxes with less than 1A draw
each. The front panel meter on the Samlex is showing a tad over 20A when
transmitting 100W in FT8/RTTY. Any suggestions? Within reason, cost isn't a
major issue.


---------------------------------------------
73 and Good DX
Peter, W2IRT

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Lovin' my K3S (S/N 10023)
73, Peter W2IRT
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Re: Silent power supply for a K3s

Leroy Buller
This is an issue that I have also, but have chosen to ignore.  I have the
samlex, astron ss30 and a rm30.   The Quiet one is the rm 30.  You might
try to tighten the bolts on the transformer.  That helped mine, but no fan.

One issue is keeping the power cord short to keep from getting a voltage
drop.  You also have to use the right gauge of wire and 45 amp power pole
connectors.   So, the power supply has to sit close to the rig.   I have a
cord of 24 inches.  I have very little voltage drop and the K3 runs better
at 13.7 than 11.8v.

So, I have learned to ignore the fans on ft8, and I wear headphones for the
other modes.

Your mileage may vary, but if it has a fan you will get noise.  The AL 82
also is noisy but that's life.

Lee K0WA

On Sun, Jun 9, 2019, 9:53 AM Peter Dougherty <[hidden email]> wrote:

> Hi all,
> I would like to find a power supply to power the K3s that is completely
> silent. I've owned an Astron RS-35M, which was great until it started
> buzzing like crazy. I swapped that out for a Samlex SEC-1235M, and did the
> fan mod to keep the fan on constantly at low speed. The problem here is
> that
> when I'm running FT8 or RTTY for more than about a half hour, the fan goes
> into high speed and stays there for an hour or more, long after the rig and
> amp's fans have shut off. And because it's a tiny fan moving a lot of air,
> it's incredibly loud.
>
> I'm looking for an RF-clean power supply (either linear or switching) that
> can deliver 25A continuously without requiring a cooling fan of any kind.
> All it's running is the K3s/P3 and a couple of boxes with less than 1A draw
> each. The front panel meter on the Samlex is showing a tad over 20A when
> transmitting 100W in FT8/RTTY. Any suggestions? Within reason, cost isn't a
> major issue.
>
>
> ---------------------------------------------
> 73 and Good DX
> Peter, W2IRT
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>
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Re: Silent power supply for a K3s

NK7Z
In reply to this post by Peter W2IRT
I found that there is a terminal block inside most Astron Power
Supplies, that sometimes gets mounted on a painted surface.

I always check all Astron supplies I buy, new or used, to insure the
paint has been removed under the ground connection of the internal
terminal block.  In about 50% of the supplies I have seen over the
years, the TB has been mounted on a painted surface.

73s and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Technical Specialist
ARRL Volunteer Examiner
ARRL Asst. Director, NW Division, Technical Resource

On 6/9/19 7:52 AM, Peter Dougherty wrote:

> Hi all,
> I would like to find a power supply to power the K3s that is completely
> silent. I've owned an Astron RS-35M, which was great until it started
> buzzing like crazy. I swapped that out for a Samlex SEC-1235M, and did the
> fan mod to keep the fan on constantly at low speed. The problem here is that
> when I'm running FT8 or RTTY for more than about a half hour, the fan goes
> into high speed and stays there for an hour or more, long after the rig and
> amp's fans have shut off. And because it's a tiny fan moving a lot of air,
> it's incredibly loud.
>
> I'm looking for an RF-clean power supply (either linear or switching) that
> can deliver 25A continuously without requiring a cooling fan of any kind.
> All it's running is the K3s/P3 and a couple of boxes with less than 1A draw
> each. The front panel meter on the Samlex is showing a tad over 20A when
> transmitting 100W in FT8/RTTY. Any suggestions? Within reason, cost isn't a
> major issue.
>
>
> ---------------------------------------------
> 73 and Good DX
> Peter, W2IRT
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>
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Re: Silent power supply for a K3s

Elecraft mailing list
In reply to this post by Peter W2IRT
 I've been running an Astron RS-35A for several years now, fortunately withoutany buzzing. However, I use it to feed a WMR PG40S, which keeps a large (105Ah)AGM SLA battery charged, and that feeds a RigRunner. I adjusted the RS-35A to14.1 V on the RigRunner (on receive), and it dips to 13.5 or so on transmitwhen running the K3 at 100W out.
As others have mentioned, it is a case of using large wire - #10 or #8 - in the shortestlengths possible, and the heavier-rated APPs throughout.
There are numerous articles out on the web and in the archives of this mailing list aboutamendments to Astron power supplies and depending on the age of yours, you may needto investigate what the root cause of the buzzing is, be it simply loose fastening hardwareor perhaps a filter capacitor that's well past its prime.
HTH,
Brandy, N1HO 
    On Sunday, June 9, 2019, 10:54:23 AM EDT, Peter Dougherty <[hidden email]> wrote:  
 
 Hi all,
I would like to find a power supply to power the K3s that is completely
silent. I've owned an Astron RS-35M, which was great until it started
buzzing like crazy.   
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Re: Silent power supply for a K3s

Nate Bargmann
In reply to this post by Peter W2IRT
Whatever you do, don't take the path I did:

https://www.worldwidedx.com/threads/megawatt-vs-chinese-imitation-30-amp-switching-power-supply-comparison.182976/page-7#post-578238

73, Nate, N0NB

--

"The optimist proclaims that we live in the best of all
possible worlds.  The pessimist fears this is true."

Web: http://www.n0nb.us  GPG key: D55A8819  GitHub: N0NB
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Re: Silent power supply for a K3s

Nate Bargmann
In reply to this post by Elecraft mailing list
I have an RM-50M at present.  To cut a lot of the audible hum I have it
setting on some plastic rings that fell out of a light fixture (d'oh!)
and it is thus supported on the bottom plate the transformer mounts to
rather than the feet of the supply.  As I have the supply under the
desk, I just reached over with my foot and by pressing on the top cover
I can cut the audible level considerably more.  I may have to
investigate a fix for this.

73, Nate, N0NB

--

"The optimist proclaims that we live in the best of all
possible worlds.  The pessimist fears this is true."

Web: http://www.n0nb.us  GPG key: D55A8819  GitHub: N0NB
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Re: Silent power supply for a K3s

Gary Johnson
In reply to this post by Peter W2IRT
I've installed modern, silent fans in nearly every piece of equipment  I
own, including my Samlex 1235. They're not expensive and come in all
standard sizes. Can't hear my PC or power supply fans at all from a few
feet away. Look for Nanoxia Deep Silence fans. (No, I'm not retrofitting
my Elecraft gear...)

https://www.amazon.com/gp/product/B00CHW8L1Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Gary NA6O

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Re: Silent power supply for a K3s

Bob McGraw - K4TAX
In reply to this post by Peter W2IRT
I'm using an Astron SS-30M with very satisfactory results.

73
Bob, K4TAX


Sent from my iPhone

> On Jun 9, 2019, at 9:52 AM, Peter Dougherty <[hidden email]> wrote:
>
> Hi all,
> I would like to find a power supply to power the K3s that is completely
> silent. I've owned an Astron RS-35M, which was great until it started
> buzzing like crazy. I swapped that out for a Samlex SEC-1235M, and did the
> fan mod to keep the fan on constantly at low speed. The problem here is that
> when I'm running FT8 or RTTY for more than about a half hour, the fan goes
> into high speed and stays there for an hour or more, long after the rig and
> amp's fans have shut off. And because it's a tiny fan moving a lot of air,
> it's incredibly loud.
>
> I'm looking for an RF-clean power supply (either linear or switching) that
> can deliver 25A continuously without requiring a cooling fan of any kind.
> All it's running is the K3s/P3 and a couple of boxes with less than 1A draw
> each. The front panel meter on the Samlex is showing a tad over 20A when
> transmitting 100W in FT8/RTTY. Any suggestions? Within reason, cost isn't a
> major issue.
>
>
> ---------------------------------------------
> 73 and Good DX
> Peter, W2IRT
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>


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Re: Silent power supply for a K3s

Jim Brown-10
In reply to this post by Peter W2IRT
On 6/9/2019 7:52 AM, Peter Dougherty wrote:
> Any suggestions? Within reason, cost isn't a
> major issue.

Sure. Another linear Astron, maybe bigger, higher power rated. I don't
know how common the buzzing problem is. As Lee suggested, tighten screws
and bolts on the one you have if you still have it.

Another important thing with Astrons is to fix their bonding problem, as
described in this link.
http://k9yc.com/PowerSupplyBondingAndAudioDistortion.pdf

BTW -- I still do the big float-charged battery thing, but it's now a
100Ah Bioenne Power LiFePO4, and the charger is a spare power supply for
one of my Thinkpads, using a  Genasun solar charge controller.  That's
not an inexpensive solution, but it IS a very good UPS for the radios,
AND the supply voltage stays above 13.2V under load as measured within
the K3, there's less IMD on TX. The Genasun controller is RF quiet, and
allows the Thinkpad PSU to charge the battery at about 7.5A. Make sure
that you buy the 14.2V version for LiFePO4 chemistry.

https://www.amazon.com/Genasun-GV-10-Li-14-2V-Controller-Lithium-Batteries/dp/B01N6AXQZH/ref=asc_df_B01N6AXQZH/?tag=hyprod-20&linkCode=df0&hvadid=198068984819&hvpos=1o4&hvnetw=g&hvrand=17014603795544971507&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032155&hvtargid=pla-354296381972&psc=1

I use a separate sealed lead-acid battery to run the other 12V stuff,
which includes antenna switching relays, LED lighting, three LCD
monitors, and several accessories. It's charged by another Thinkpad PSU
with a lead-acid version of the same Genasun controller.  I do, of
course, have multi-turn ferrite chokes on the chargers and on the LCD
monitor power and video lines.

For about half of my contesting, my K3s run at about 50W driving an 87A
or 25W driving a KPA500, and this DC power arrangement has no trouble
keeping up.

73, Jim K9YC

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Re: Silent power supply for a K3s

Leroy Buller
As alway...way cool.

Lee K0WA

On Sun, Jun 9, 2019, 6:16 PM Jim Brown <[hidden email]> wrote:

> On 6/9/2019 7:52 AM, Peter Dougherty wrote:
> > Any suggestions? Within reason, cost isn't a
> > major issue.
>
> Sure. Another linear Astron, maybe bigger, higher power rated. I don't
> know how common the buzzing problem is. As Lee suggested, tighten screws
> and bolts on the one you have if you still have it.
>
> Another important thing with Astrons is to fix their bonding problem, as
> described in this link.
> http://k9yc.com/PowerSupplyBondingAndAudioDistortion.pdf
>
> BTW -- I still do the big float-charged battery thing, but it's now a
> 100Ah Bioenne Power LiFePO4, and the charger is a spare power supply for
> one of my Thinkpads, using a  Genasun solar charge controller.  That's
> not an inexpensive solution, but it IS a very good UPS for the radios,
> AND the supply voltage stays above 13.2V under load as measured within
> the K3, there's less IMD on TX. The Genasun controller is RF quiet, and
> allows the Thinkpad PSU to charge the battery at about 7.5A. Make sure
> that you buy the 14.2V version for LiFePO4 chemistry.
>
>
> https://www.amazon.com/Genasun-GV-10-Li-14-2V-Controller-Lithium-Batteries/dp/B01N6AXQZH/ref=asc_df_B01N6AXQZH/?tag=hyprod-20&linkCode=df0&hvadid=198068984819&hvpos=1o4&hvnetw=g&hvrand=17014603795544971507&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032155&hvtargid=pla-354296381972&psc=1
>
> I use a separate sealed lead-acid battery to run the other 12V stuff,
> which includes antenna switching relays, LED lighting, three LCD
> monitors, and several accessories. It's charged by another Thinkpad PSU
> with a lead-acid version of the same Genasun controller.  I do, of
> course, have multi-turn ferrite chokes on the chargers and on the LCD
> monitor power and video lines.
>
> For about half of my contesting, my K3s run at about 50W driving an 87A
> or 25W driving a KPA500, and this DC power arrangement has no trouble
> keeping up.
>
> 73, Jim K9YC
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
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Re: Silent power supply for a K3s

Richard Zalewski
I did two of the Samlex and returned them both.  The fan problem drove me
crazy.  I replaced it with a MFJ-4230MV and love it.  Quiet cool and good
metering.

Richard
*W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF, W0MQU,
J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ, XE2DV


*Be joyful in hope, patient in affliction, faithful in prayer*


On Sun, Jun 9, 2019 at 4:39 PM Leroy Buller <[hidden email]> wrote:

> As alway...way cool.
>
> Lee K0WA
>
> On Sun, Jun 9, 2019, 6:16 PM Jim Brown <[hidden email]> wrote:
>
> > On 6/9/2019 7:52 AM, Peter Dougherty wrote:
> > > Any suggestions? Within reason, cost isn't a
> > > major issue.
> >
> > Sure. Another linear Astron, maybe bigger, higher power rated. I don't
> > know how common the buzzing problem is. As Lee suggested, tighten screws
> > and bolts on the one you have if you still have it.
> >
> > Another important thing with Astrons is to fix their bonding problem, as
> > described in this link.
> > http://k9yc.com/PowerSupplyBondingAndAudioDistortion.pdf
> >
> > BTW -- I still do the big float-charged battery thing, but it's now a
> > 100Ah Bioenne Power LiFePO4, and the charger is a spare power supply for
> > one of my Thinkpads, using a  Genasun solar charge controller.  That's
> > not an inexpensive solution, but it IS a very good UPS for the radios,
> > AND the supply voltage stays above 13.2V under load as measured within
> > the K3, there's less IMD on TX. The Genasun controller is RF quiet, and
> > allows the Thinkpad PSU to charge the battery at about 7.5A. Make sure
> > that you buy the 14.2V version for LiFePO4 chemistry.
> >
> >
> >
> https://www.amazon.com/Genasun-GV-10-Li-14-2V-Controller-Lithium-Batteries/dp/B01N6AXQZH/ref=asc_df_B01N6AXQZH/?tag=hyprod-20&linkCode=df0&hvadid=198068984819&hvpos=1o4&hvnetw=g&hvrand=17014603795544971507&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032155&hvtargid=pla-354296381972&psc=1
> >
> > I use a separate sealed lead-acid battery to run the other 12V stuff,
> > which includes antenna switching relays, LED lighting, three LCD
> > monitors, and several accessories. It's charged by another Thinkpad PSU
> > with a lead-acid version of the same Genasun controller.  I do, of
> > course, have multi-turn ferrite chokes on the chargers and on the LCD
> > monitor power and video lines.
> >
> > For about half of my contesting, my K3s run at about 50W driving an 87A
> > or 25W driving a KPA500, and this DC power arrangement has no trouble
> > keeping up.
> >
> > 73, Jim K9YC
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
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> Message delivered to [hidden email]
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Re: Silent power supply for a K3s

Michael Walker
How old was the RS35 before it started to buzz?

Could this be as simple as buying another RS35?

Mike va3mw


On Sun, Jun 9, 2019 at 7:54 PM Richard Zalewski <[hidden email]> wrote:

> I did two of the Samlex and returned them both.  The fan problem drove me
> crazy.  I replaced it with a MFJ-4230MV and love it.  Quiet cool and good
> metering.
>
> Richard
> *W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF, W0MQU,
> J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ, XE2DV
>
>
> *Be joyful in hope, patient in affliction, faithful in prayer*
>
>
> On Sun, Jun 9, 2019 at 4:39 PM Leroy Buller <[hidden email]> wrote:
>
> > As alway...way cool.
> >
> > Lee K0WA
> >
> > On Sun, Jun 9, 2019, 6:16 PM Jim Brown <[hidden email]>
> wrote:
> >
> > > On 6/9/2019 7:52 AM, Peter Dougherty wrote:
> > > > Any suggestions? Within reason, cost isn't a
> > > > major issue.
> > >
> > > Sure. Another linear Astron, maybe bigger, higher power rated. I don't
> > > know how common the buzzing problem is. As Lee suggested, tighten
> screws
> > > and bolts on the one you have if you still have it.
> > >
> > > Another important thing with Astrons is to fix their bonding problem,
> as
> > > described in this link.
> > > http://k9yc.com/PowerSupplyBondingAndAudioDistortion.pdf
> > >
> > > BTW -- I still do the big float-charged battery thing, but it's now a
> > > 100Ah Bioenne Power LiFePO4, and the charger is a spare power supply
> for
> > > one of my Thinkpads, using a  Genasun solar charge controller.  That's
> > > not an inexpensive solution, but it IS a very good UPS for the radios,
> > > AND the supply voltage stays above 13.2V under load as measured within
> > > the K3, there's less IMD on TX. The Genasun controller is RF quiet, and
> > > allows the Thinkpad PSU to charge the battery at about 7.5A. Make sure
> > > that you buy the 14.2V version for LiFePO4 chemistry.
> > >
> > >
> > >
> >
> https://www.amazon.com/Genasun-GV-10-Li-14-2V-Controller-Lithium-Batteries/dp/B01N6AXQZH/ref=asc_df_B01N6AXQZH/?tag=hyprod-20&linkCode=df0&hvadid=198068984819&hvpos=1o4&hvnetw=g&hvrand=17014603795544971507&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032155&hvtargid=pla-354296381972&psc=1
> > >
> > > I use a separate sealed lead-acid battery to run the other 12V stuff,
> > > which includes antenna switching relays, LED lighting, three LCD
> > > monitors, and several accessories. It's charged by another Thinkpad PSU
> > > with a lead-acid version of the same Genasun controller.  I do, of
> > > course, have multi-turn ferrite chokes on the chargers and on the LCD
> > > monitor power and video lines.
> > >
> > > For about half of my contesting, my K3s run at about 50W driving an 87A
> > > or 25W driving a KPA500, and this DC power arrangement has no trouble
> > > keeping up.
> > >
> > > 73, Jim K9YC
> > >
> > > ______________________________________________________________
> > > Elecraft mailing list
> > > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > > Help: http://mailman.qth.net/mmfaq.htm
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Re: Silent power supply for a K3s

Jim - N4ST
In reply to this post by Richard Zalewski
I don't know how common it is, but eHam lists several failures of the
MFJ-4230MV supply that took out the rig attached to it.
Looking at the reviews they are pretty much a 5 (love it) or a 0 (it smoked
my rig when it failed).

________
73,
Jim - N4ST


-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Richard Zalewski
Sent: Sunday, June 9, 2019 19:53
To: Leroy Buller <[hidden email]>
Cc: Elecraft Reflector <[hidden email]>
Subject: Re: [Elecraft] Silent power supply for a K3s

I did two of the Samlex and returned them both.  The fan problem drove me
crazy.  I replaced it with a MFJ-4230MV and love it.  Quiet cool and good
metering.

Richard
*W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF, W0MQU,
J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ, XE2DV


*Be joyful in hope, patient in affliction, faithful in prayer*

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Re: Silent power supply for a K3s

VE3NR
How would a switched PS take out a radio?

Bert VE3NR



On 6/9/2019 11:40 PM, Jim - N4ST wrote:

> I don't know how common it is, but eHam lists several failures of the
> MFJ-4230MV supply that took out the rig attached to it.
> Looking at the reviews they are pretty much a 5 (love it) or a 0 (it smoked
> my rig when it failed).
>
> ________
> 73,
> Jim - N4ST
>
>
> -----Original Message-----
> From: [hidden email] <[hidden email]> On
> Behalf Of Richard Zalewski
> Sent: Sunday, June 9, 2019 19:53
> To: Leroy Buller <[hidden email]>
> Cc: Elecraft Reflector <[hidden email]>
> Subject: Re: [Elecraft] Silent power supply for a K3s
>
> I did two of the Samlex and returned them both.  The fan problem drove me
> crazy.  I replaced it with a MFJ-4230MV and love it.  Quiet cool and good
> metering.
>
> Richard
> *W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF, W0MQU,
> J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ, XE2DV
>
>
> *Be joyful in hope, patient in affliction, faithful in prayer*
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

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Re: Silent power supply for a K3s

Charlie T, K3ICH
Any supply that is regulated, whether a switching or linear regulator
circuit is used, has the potential to "take-out" the radio because if the
regulating circuit fails, the un-regulated voltage which is normally
significantly higher than the regulated voltage will be applied to the
radio. In a 12 - 14 V supply, this could very well damage anything it is
connected to, from a simple 12V light bulb to your fancy new SS radio.

That said, many good quality commercial power supplies have what is called a
"crow-bar" circuit which is essentially a big SCR across the supply's
output, with its gate driven by a voltage sensing circuit set a level
slightly higher than the supply's normal output, say 16V. The action is if
the regulator fails, the sensing circuit fires the SCR, which is hopefully
big enough to effectively short the power supply's output and ether trigger
a fold-back current limiting * circuit, or blow a fuse.


73, Charlie k3ICH

*Unfortunately, in many supplies, the current limiter AND voltage regulator
use the same active device, so in a fault situation, blowing the fuse is the
last resort to a safe shut down.

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Bert
Sent: Monday, June 10, 2019 12:16 AM
To: [hidden email]
Subject: Re: [Elecraft] Silent power supply for a K3s

How would a switched PS take out a radio?

Bert VE3NR



On 6/9/2019 11:40 PM, Jim - N4ST wrote:

> I don't know how common it is, but eHam lists several failures of the
> MFJ-4230MV supply that took out the rig attached to it.
> Looking at the reviews they are pretty much a 5 (love it) or a 0 (it
> smoked my rig when it failed).
>
> ________
> 73,
> Jim - N4ST
>
>
> -----Original Message-----
> From: [hidden email]
> <[hidden email]> On Behalf Of Richard Zalewski
> Sent: Sunday, June 9, 2019 19:53
> To: Leroy Buller <[hidden email]>
> Cc: Elecraft Reflector <[hidden email]>
> Subject: Re: [Elecraft] Silent power supply for a K3s
>
> I did two of the Samlex and returned them both.  The fan problem drove
> me crazy.  I replaced it with a MFJ-4230MV and love it.  Quiet cool
> and good metering.
>
> Richard
> *W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF,
> W0MQU, J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ,
> XE2DV
>
>
> *Be joyful in hope, patient in affliction, faithful in prayer*
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net Please help support this email
> list: http://www.qsl.net/donate.html Message delivered to
> [hidden email]

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Re: Silent power supply for a K3s

Peter W2IRT
In reply to this post by Bob McGraw - K4TAX
I think that's probably going to be the winner for me if it is indeed silent
(or near-silent). Thanks Bob!

 - pjd

-----Original Message-----
From: Bob McGraw K4TAX <[hidden email]>
Sent: Sunday, June 9, 2019 1:57 PM
To: Peter Dougherty <[hidden email]>
Cc: [hidden email]
Subject: Re: [Elecraft] Silent power supply for a K3s

I'm using an Astron SS-30M with very satisfactory results.

73
Bob, K4TAX


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Lovin' my K3S (S/N 10023)
73, Peter W2IRT
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Re: Silent power supply for a K3s

K9MA
In reply to this post by VE3NR
On 6/9/2019 23:16, Bert wrote:
> How would a switched PS take out a radio?
>
> Bert VE3NR

Most likely due to overvoltage. Linear supplies are particularly
susceptible, as the series pass transistor is under stress and can
short. Switching supplies can fail if the voltage feedback loop somehow
opens up. I've not heard of it happening, but all it would take would be
one failed resistor or solder joint. I use a switching supply for my K3,
but I built an external overvoltage protector. Of course, the supply has
never failed.

BTW, I've found that the fan noise from the Samlex SEC-1235 is never
audible above the K3 fans, except during long periods of receive, when
the low speed supply fan is just barely audible. (I did the mod, so the
supply fan runs at low speed all the time.) If I transmit long enough
for the supply fan to switch to full speed, the K3 fans are already
running fast enough to drown it out. Not to mention those in the KPA-1500.

I'm very happy with the Samlex supply. I've never detected a trace of
RFI from it.

73,

Scott K9MA

--
Scott  K9MA

[hidden email]

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Switched PS overvoltage

VE3NR
I haven't experienced that a switched PS causes overvoltage. They
usually just die!

Bert VE3NR


On 6/10/2019 11:12 AM, K9MA wrote:

> On 6/9/2019 23:16, Bert wrote:
>> How would a switched PS take out a radio?
>>
>> Bert VE3NR
>
> Most likely due to overvoltage. Linear supplies are particularly
> susceptible, as the series pass transistor is under stress and can
> short. Switching supplies can fail if the voltage feedback loop
> somehow opens up. I've not heard of it happening, but all it would
> take would be one failed resistor or solder joint. I use a switching
> supply for my K3, but I built an external overvoltage protector. Of
> course, the supply has never failed.
>
> BTW, I've found that the fan noise from the Samlex SEC-1235 is never
> audible above the K3 fans, except during long periods of receive, when
> the low speed supply fan is just barely audible. (I did the mod, so
> the supply fan runs at low speed all the time.) If I transmit long
> enough for the supply fan to switch to full speed, the K3 fans are
> already running fast enough to drown it out. Not to mention those in
> the KPA-1500.
>
> I'm very happy with the Samlex supply. I've never detected a trace of
> RFI from it.
>
> 73,
>
> Scott K9MA
>

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Re: Switched PS overvoltage

K9MA
It's far less likely that a switcher will fail to overvoltage. The
switching transistor(s) under stress, and most likely to fail, will just
cause the supply to die, as you have observed.

Still, I don't like entrusting the life of my K3 to one cheap resistor
in the feedback loop. That comes of a career designing spacecraft
electronics.

73,
Scott K9MA

On 6/10/2019 11:01, Bert wrote:

> I haven't experienced that a switched PS causes overvoltage. They
> usually just die!
>
> Bert VE3NR
>
>
> On 6/10/2019 11:12 AM, K9MA wrote:
>> On 6/9/2019 23:16, Bert wrote:
>>> How would a switched PS take out a radio?
>>>
>>> Bert VE3NR
>>
>> Most likely due to overvoltage. Linear supplies are particularly
>> susceptible, as the series pass transistor is under stress and can
>> short. Switching supplies can fail if the voltage feedback loop
>> somehow opens up. I've not heard of it happening, but all it would
>> take would be one failed resistor or solder joint. I use a switching
>> supply for my K3, but I built an external overvoltage protector. Of
>> course, the supply has never failed.
>>
>> BTW, I've found that the fan noise from the Samlex SEC-1235 is never
>> audible above the K3 fans, except during long periods of receive,
>> when the low speed supply fan is just barely audible. (I did the mod,
>> so the supply fan runs at low speed all the time.) If I transmit long
>> enough for the supply fan to switch to full speed, the K3 fans are
>> already running fast enough to drown it out. Not to mention those in
>> the KPA-1500.
>>
>> I'm very happy with the Samlex supply. I've never detected a trace of
>> RFI from it.
>>
>> 73,
>>
>> Scott K9MA
>>
>
> ______________________________________________________________
> Elecraft mailing list
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>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]


--
Scott  K9MA

[hidden email]

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Re: Silent power supply for a K3s

Gmail - George
In reply to this post by Charlie T, K3ICH
Astron has an Over-Voltage protection option that is an add-on accessory.

In the past it was an option or included on some models.
If the regulation series transistor shorts or the regulation circuits
malfunctions, then the over-voltage protection shorts the output and blows
the fuse(s).

My present RS-35M included it in the purchase.
Since the late 70s or early 80s, I have used various current rated Astrons
in both 12 and 24 volts with few if any issues except when Florida Flash &
Flicker passed an EMP or such down the line!

BTW - Never have heard it and it is well over 10 years old.

George  AI4VZ

-----Original Message-----
From: Charlie T
Sent: Monday, June 10, 2019 7:57 AM
To: [hidden email]
Subject: Re: [Elecraft] Silent power supply for a K3s

Any supply that is regulated, whether a switching or linear regulator
circuit is used, has the potential to "take-out" the radio because if the
regulating circuit fails, the un-regulated voltage which is normally
significantly higher than the regulated voltage will be applied to the
radio. In a 12 - 14 V supply, this could very well damage anything it is
connected to, from a simple 12V light bulb to your fancy new SS radio.

That said, many good quality commercial power supplies have what is called a
"crow-bar" circuit which is essentially a big SCR across the supply's
output, with its gate driven by a voltage sensing circuit set a level
slightly higher than the supply's normal output, say 16V. The action is if
the regulator fails, the sensing circuit fires the SCR, which is hopefully
big enough to effectively short the power supply's output and ether trigger
a fold-back current limiting * circuit, or blow a fuse.


73, Charlie k3ICH

*Unfortunately, in many supplies, the current limiter AND voltage regulator
use the same active device, so in a fault situation, blowing the fuse is the
last resort to a safe shut down.

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Bert
Sent: Monday, June 10, 2019 12:16 AM
To: [hidden email]
Subject: Re: [Elecraft] Silent power supply for a K3s

How would a switched PS take out a radio?

Bert VE3NR



On 6/9/2019 11:40 PM, Jim - N4ST wrote:

> I don't know how common it is, but eHam lists several failures of the
> MFJ-4230MV supply that took out the rig attached to it.
> Looking at the reviews they are pretty much a 5 (love it) or a 0 (it
> smoked my rig when it failed).
>
> ________
> 73,
> Jim - N4ST
>
>
> -----Original Message-----
> From: [hidden email]
> <[hidden email]> On Behalf Of Richard Zalewski
> Sent: Sunday, June 9, 2019 19:53
> To: Leroy Buller <[hidden email]>
> Cc: Elecraft Reflector <[hidden email]>
> Subject: Re: [Elecraft] Silent power supply for a K3s
>
> I did two of the Samlex and returned them both.  The fan problem drove
> me crazy.  I replaced it with a MFJ-4230MV and love it.  Quiet cool
> and good metering.
>
> Richard
> *W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF,
> W0MQU, J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ,
> XE2DV
>
>
> *Be joyful in hope, patient in affliction, faithful in prayer*
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net Please help support this email
> list: http://www.qsl.net/donate.html Message delivered to
> [hidden email]

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12