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KXPA100 Thermal Fault

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KXPA100 Thermal Fault

I used my KX3/KXPA100 in the NAQP RTTY contest this weekend. The KX3 with
added-on heat sink worked very well; however, the KXPA100 repeatedly faulted
with HI TEMPERATURE indicated on the KX3 at full output after prolonged
operating (lots of CQ'ing with short pause intervals). PA.X temp indicated at
failure was around 60C...as it should. Shack temperature was around 70
degrees F
Yes, I know all about digital modes and full power stressing amplifiers,
etc. What I want to know is how to mitigate this interruption yet run full
output. To that end, I have a couple ideas: what if I mounted the amp
vertically so the heatsink fins "drew" cooler air through themselves via
convection? Secondly, would a couple muffin fans mounted atop the cooling fins do
the job?
The net of this is that I'd like to enjoy the full benefit of having a
high-quality 100-Watt amplifier, regardless of mode or key-down time.

Bert N4CW/K1IMI
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Elecraft mailing list

Re: KXPA100 Thermal Fault

Why not run it at 50 watts and give up the 3db. Probably will not make a difference in number of contacts and your thermal problem should go away. Also what is SWR

George, W6GF

On Sunday, July 20, 2014 4:23 PM, Bert via Elecraft <[hidden email]> wrote:

I used my KX3/KXPA100 in the NAQP RTTY contest this weekend. The KX3 with
added-on heat sink worked very well; however, the KXPA100 repeatedly faulted
with HI TEMPERATURE indicated on the KX3 at full output after prolonged
operating (lots of CQ'ing with short pause intervals). PA.X temp indicated at
failure was around 60C...as it should. Shack temperature was around 70
degrees F
Yes, I know all about digital modes and full power stressing amplifiers,
etc. What I want to know is how to mitigate this interruption yet run full
output. To that end, I have a couple ideas: what if I mounted the amp
vertically so the heatsink fins "drew" cooler air through themselves via
convection? Secondly, would a couple muffin fans mounted atop the cooling fins do
the job?
The net of this is that I'd like to enjoy the full benefit of having a
high-quality 100-Watt amplifier, regardless of mode or key-down time.

Bert N4CW/K1IMI
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NK7Z

Re: KXPA100 Thermal Fault

Fans are always good... I saw someone selling a thermostatically
controlled fan for 70 bucks recently... Built for whatever you want to
use it on. I wish I knew where he got his thermostat from... I would
build it myself... Can't bring myself to spend 70 bucks on a fan.
--
Thanks and 73's,
For equipment, and software setups and reviews see:
www.nk7z.net
for MixW support see;
http://groups.yahoo.com/neo/groups/mixw/info
for Dopplergram information see:
http://groups.yahoo.com/neo/groups/dopplergram/info
for MM-SSTV see:
http://groups.yahoo.com/neo/groups/MM-SSTV/info

On Sun, 2014-07-20 at 16:54 -0700, george fritkin via Elecraft wrote:

> Why not run it at 50 watts and give up the 3db. Probably will not make a difference in number of contacts and your thermal problem should go away. Also what is SWR
>
> George, W6GF
>
>
> On Sunday, July 20, 2014 4:23 PM, Bert via Elecraft <[hidden email]> wrote:
>
>
>
> I used my KX3/KXPA100 in the NAQP RTTY contest this weekend. The KX3 with
> added-on heat sink worked very well; however, the KXPA100 repeatedly faulted
> with HI TEMPERATURE indicated on the KX3 at full output after prolonged
> operating (lots of CQ'ing with short pause intervals). PA.X temp indicated at
> failure was around 60C...as it should. Shack temperature was around 70
> degrees F
> Yes, I know all about digital modes and full power stressing amplifiers,
> etc. What I want to know is how to mitigate this interruption yet run full
> output. To that end, I have a couple ideas: what if I mounted the amp
> vertically so the heatsink fins "drew" cooler air through themselves via
> convection? Secondly, would a couple muffin fans mounted atop the cooling fins do
> the job?
> The net of this is that I'd like to enjoy the full benefit of having a
> high-quality 100-Watt amplifier, regardless of mode or key-down time.
>
> Bert N4CW/K1IMI
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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> Elecraft mailing list
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Edward R Cole

Re: KXPA100 Thermal Fault

In reply to this post by Elecraft mailing list

Subject: [Elecraft] KXPA100 Thermal Fault
Message-ID: <[hidden email]>
Content-Type: text/plain; charset="US-ASCII"

I used my KX3/KXPA100 in the NAQP RTTY contest this weekend. The KX3 with
added-on heat sink worked very well; however, the KXPA100 repeatedly faulted
with HI TEMPERATURE indicated on the KX3 at full output after prolonged
operating (lots of CQ'ing with short pause intervals). PA.X temp indicated at
failure was around 60C...as it should. Shack temperature was around 70
degrees F
Yes, I know all about digital modes and full power stressing amplifiers,
etc. What I want to know is how to mitigate this interruption yet run full
output. To that end, I have a couple ideas: what if I mounted the amp
vertically so the heatsink fins "drew" cooler air through themselves via
convection? Secondly, would a couple muffin fans mounted atop the
cooling fins do
the job?
The net of this is that I'd like to enjoy the full benefit of having a
high-quality 100-Watt amplifier, regardless of mode or key-down time.

Bert N4CW/K1IMI
---------------------
Bert,

Using radial "muffin' fans to cool amps running digital modes is
standard practise to save the amps from heat stress failures. Just
get enough to cover the surface area of the heat sink fins and you
should find that it has solved the issue for the KXPA100. Fin
orientation is not important in that case. Note the 100w amp in the
K3 has two fans.

I run two fans on my 170w 2m linear and all my transverters have fans
on the heat sinks. I simply laid a 4-inch fan on top of my 150w 6m
amp to keep it cool when running JT65. I'm thinking of adding a fan
on my 15w 900-MHz FM transceiver for a little insurance.

Note: I added a heat sink to my KX3.

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

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Elecraft mailing list

Re: KXPA100 Thermal Fault

In reply to this post by Elecraft mailing list

Thanks to all who made suggestions. I will be trying one or two fans atop
the heat sink and see how that works out in the next RTTY contest foray.
While looking into possibilities, I checked out the web site where I got my
"add-on" KX3 heat sink (https://proaudioeng.com/products/) and found they
had added a new product, a power supply specifically for the KX3. Specs
look promising. [I don't have a vested interest in the company, just pleased
with the heat sink.]
Again, this reflector is a great source for ideas about great products!
73, Bert N4CW/K1IMI

In a message dated 7/20/2014 7:18:48 P.M. Eastern Daylight Time,
[hidden email] writes:

I used my KX3/KXPA100 in the NAQP RTTY contest this weekend. The KX3 with
added-on heat sink worked very well; however, the KXPA100 repeatedly faulted
with HI TEMPERATURE indicated on the KX3 at full output after prolonged
operating (lots of CQ'ing with short pause intervals). PA.X temp indicated at
failure was around 60C...as it should. Shack temperature was around 70
degrees F
Yes, I know all about digital modes and full power stressing amplifiers,
etc. What I want to know is how to mitigate this interruption yet run full
output. To that end, I have a couple ideas: what if I mounted the amp
vertically so the heatsink fins "drew" cooler air through themselves via
convection? Secondly, would a couple muffin fans mounted atop the cooling fins do
the job?
The net of this is that I'd like to enjoy the full benefit of having a
high-quality 100-Watt amplifier, regardless of mode or key-down time.

Bert N4CW/K1IMI

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rgconner

Re: KXPA100 Thermal Fault

In reply to this post by NK7Z

Crazy. Find one from Newegg for far less.
On Jul 20, 2014 5:25 PM, "David Cole" <[hidden email]> wrote:

> Fans are always good... I saw someone selling a thermostatically
> controlled fan for 70 bucks recently... Built for whatever you want to
> use it on. I wish I knew where he got his thermostat from... I would
> build it myself... Can't bring myself to spend 70 bucks on a fan.
> --
> Thanks and 73's,
> For equipment, and software setups and reviews see:
> www.nk7z.net
> for MixW support see;
> http://groups.yahoo.com/neo/groups/mixw/info
> for Dopplergram information see:
> http://groups.yahoo.com/neo/groups/dopplergram/info
> for MM-SSTV see:
> http://groups.yahoo.com/neo/groups/MM-SSTV/info
>
>
> On Sun, 2014-07-20 at 16:54 -0700, george fritkin via Elecraft wrote:
> > Why not run it at 50 watts and give up the 3db. Probably will not make
> a difference in number of contacts and your thermal problem should go away.
> Also what is SWR
> >
> > George, W6GF
> >
> >
> > On Sunday, July 20, 2014 4:23 PM, Bert via Elecraft <
> [hidden email]> wrote:
> >
> >
> >
> > I used my KX3/KXPA100 in the NAQP RTTY contest this weekend. The KX3 with
> > added-on heat sink worked very well; however, the KXPA100 repeatedly
> faulted
> > with HI TEMPERATURE indicated on the KX3 at full output after prolonged
> > operating (lots of CQ'ing with short pause intervals). PA.X temp
> indicated at
> > failure was around 60C...as it should. Shack temperature was around 70
> > degrees F
> > Yes, I know all about digital modes and full power stressing amplifiers,
> > etc. What I want to know is how to mitigate this interruption yet run
> full
> > output. To that end, I have a couple ideas: what if I mounted the amp
> > vertically so the heatsink fins "drew" cooler air through themselves via
> > convection? Secondly, would a couple muffin fans mounted atop the
> cooling fins do
> > the job?
> > The net of this is that I'd like to enjoy the full benefit of having a
> > high-quality 100-Watt amplifier, regardless of mode or key-down time.
> >
> > Bert N4CW/K1IMI
> > ______________________________________________________________
> > 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]
> >
> > 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
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> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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>

vk2rq

Re: KXPA100 Thermal Fault

In reply to this post by Elecraft mailing list

Make sure you put the fans the right way around, ie. sucking up the hot air and blowing it away from the heat sink :-)

73, Matt VK2RQ

> On 22 Jul 2014, at 9:18 am, Bert via Elecraft <[hidden email]> wrote:
>
> Thanks to all who made suggestions. I will be trying one or two fans atop
> the heat sink and see how that works out in the next RTTY contest foray.
> While looking into possibilities, I checked out the web site where I got my
> "add-on" KX3 heat sink (https://proaudioeng.com/products/) and found they
> had added a new product, a power supply specifically for the KX3. Specs
> look promising. [I don't have a vested interest in the company, just pleased
> with the heat sink.]
> Again, this reflector is a great source for ideas about great products!
> 73, Bert N4CW/K1IMI
>
>
> In a message dated 7/20/2014 7:18:48 P.M. Eastern Daylight Time,
> [hidden email] writes:
>
> I used my KX3/KXPA100 in the NAQP RTTY contest this weekend. The KX3 with
> added-on heat sink worked very well; however, the KXPA100 repeatedly faulted
> with HI TEMPERATURE indicated on the KX3 at full output after prolonged
> operating (lots of CQ'ing with short pause intervals). PA.X temp indicated at
> failure was around 60C...as it should. Shack temperature was around 70
> degrees F
> Yes, I know all about digital modes and full power stressing amplifiers,
> etc. What I want to know is how to mitigate this interruption yet run full
> output. To that end, I have a couple ideas: what if I mounted the amp
> vertically so the heatsink fins "drew" cooler air through themselves via
> convection? Secondly, would a couple muffin fans mounted atop the cooling fins do
> the job?
> The net of this is that I'd like to enjoy the full benefit of having a
> high-quality 100-Watt amplifier, regardless of mode or key-down time.
>
> Bert N4CW/K1IMI
>
> ______________________________________________________________
> 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]

Bob N3MNT

Re: KXPA100 Thermal Fault

This looks like a a relatively inexpensive solution to the temp controlled fan idea. They seem to have a reputation for being quiet and reliable.
http://sitesearch.outletpc.com/search?page=1&query=Gelid+FN-TX12-15+Silent+++ON1266+++++++++1+++9.98++Warranty+%3D+30-Day+Warranty+Included+12+TC+120mm+3pin+1500RPM+++++++++++++++++++++++++++%28%2B0.00%29+Temp+Control+Case+Fan&I1.x=55&I1.y=3

Don Wilhelm-4

Re: KXPA100 Thermal Fault

Salvage a 12 volt muffin fan from a defunct computer and put a resistor
in series with it to slow it down. Almost whisper quiet, but it can
substantially increase the air flow over the heatsink and keep it cool.
Cost, almost nothing. But put a shield over it to keep fingers out of
the blades.

73,
Don W3FPR

On 7/22/2014 6:18 PM, Bob N3MNT wrote:
> This looks like a a relatively inexpensive solution to the temp controlled
> fan idea. They seem to have a reputation for being quiet and reliable.
> http://sitesearch.outletpc.com/search?page=1&query=Gelid+FN-TX12-15+Silent+++ON1266+++++++++1+++9.98++Warranty+%3D+30-Day+Warranty+Included+12+TC+120mm+3pin+1500RPM+++++++++++++++++++++++++++%28%2B0.00%29+Temp+Control+Case+Fan&I1.x=55&I1.y=3
>
>
>

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JHRichards

Re: KXPA100 Thermal Fault

I did that on two of my radios, and built a simple clamp on bracket to
mount them without modifying the original heat sink fins. Cost of my
project was approx. $7 for the fan, and $1.5 for some aluminum stock.

I was particular careful to select fans with clearly stated noise
figures. Not all vendors publish the noise figures, but those with less
than 20 dBA are fairly quiet, and, as Don says, if you slow them down a
bit, they will move a lot of air over time, and you will never hear
them. I can provide photos if anyone is interested in how I mounted mine.

---------------------- K8JHR ---------------------

On 7/22/2014 7:04 PM, Don Wilhelm wrote:
> Salvage a 12 volt muffin fan from a defunct computer and put a resistor
> in series with it to slow it down. Almost whisper quiet, but it can
> substantially increase the air flow over the heatsink and keep it cool.
> Cost, almost nothing. But put a shield over it to keep fingers out of
> the blades.
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Lynn W. Taylor, WB6UUT

Re: KXPA100 Thermal Fault

In reply to this post by Don Wilhelm-4

On 7/22/2014 4:04 PM, Don Wilhelm wrote:
> Salvage a 12 volt muffin fan from a defunct computer and put a
> resistor in series with it to slow it down.
Salvage a 12v muffin fan, and run it off of a 7 volt wall-wart.
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