Re: [Elecraft] Cooling Fans

[Tom Doligalski via Elecraft]

I finally had the fans go off sporadically again, while I was monitoring the 
temperature. At that time conditions were:

Voltage 13.2 V
Current: 1.3 A (second receiver off)
PA 35 C
FP 41 C

This was after the K3 had been “idling” all night, with no transmissions and 
volume turned down to 0. 

These are also the same values that the K3 normally shows…I am to receive a new 
thermometer later today, and will be calibrating the K3. 

Strange!

Tom W4KX

> On Jul 19, 2020, at 2:59 PM, Mike Harris via Elecraft 
>  wrote:
> 
> Hi,
> 
> FWIW.
> 
> Test conditions measured under the K3 DISP menu:
> 
> 14.1V
> 1.38A Sub RX on
> PA 32C
> FP 40C
> 
> PA fans off
> PA fans on/off at 36C/35C
> 
> Room temp 22C
> 
> K3 FP and PA temp sensors calibrated against a laboratory thermometer 
> adjacent to the K3.
> 
> Never really noticed when the PA fans come on in idle conditions due to PC 
> fan noise.
> 
> Regards,
> 
> Mike VP8NO
> 
> On 19/07/2020 12:15, John Simmons wrote:
> > Tom,
> >
> > Interesting post. I thought this was the case with my K3 also, but i 
> > figured out later that it was the fan in my power supply instead. Poor 
> > hearing!
> >
> > -de John NI0K
> >
> > Tom Doligalski via Elecraft wrote on 7/19/2020 8:41 AM:
> >> I am the original owner of K3/100 #969, which still works great.
> >>
> >> I’ve noticed that recently the cooling fan comes on occasionally even if 
> >> the radio is on, but not in use (volume down, no transmitting). FP 
> >> temperature shows 41 C, and PA temperature is at 35 C
> >>
> >> This is not at objectionable at all, but made me wonder if this was a 
> >> cause for concern.
> >>
> >> Any ideas?
> >>
> >> Tom W4KX
> 
> On 19/07/2020 12:15, John Simmons wrote:
>> Tom,
>> Interesting post. I thought this was the case with my K3 also, but i figured 
>> out later that it was the fan in my power supply instead. Poor hearing!
>> -de John NI0K
>> Tom Doligalski via Elecraft wrote on 7/19/2020 8:41 AM:
>>> I am the original owner of K3/100 #969, which still works great.
>>> 
>>> I’ve noticed that recently the cooling fan comes on occasionally even if 
>>> the radio is on, but not in use (volume down, no transmitting). FP 
>>> temperature shows 41 C, and PA temperature is at 35 C
>>> 
>>> This is not at objectionable at all, but made me wonder if this was a cause 
>>> for concern.
>>> 
>>> Any ideas?
>>> 
>>> Tom W4KX
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Re: [Elecraft] Cooling Fans

[Joe DeVincentis]

Personally, I wouldn't be concerned about the radio just yet.  There's a couple 
of other variables to check first.

How's the air flow around the radio? 

What's the ambient temp right around the radio (not the room, but right next to 
the radio)?

Any thing sitting on top of the radio?  Heat needs an easy escape.

Any heat generating items near the radio (e.g. incandescent lights)?


BTW, if the fan noise is objectionable, you can replace the fans with Noctua 
fans that have very similar characteristics and are quieter.  I used Noctua 
NF-A6x25 FLX fans.  The specs were almost identical and the fans are quieter.  

Here's a post regarding the fan replacement: 
http://elecraft.365791.n2.nabble.com/K3-Fan-Replacement-td7592075.html 
.  No 
modifications to the K3s was needed.  

Joe, KO8V


> On Jul 19, 2020, at 09:41, Tom Doligalski via Elecraft 
>  wrote:
> 
> I am the original owner of K3/100 #969, which still works great. 
> 
> I’ve noticed that recently the cooling fan comes on occasionally even if the 
> radio is on, but not in use (volume down, no transmitting). FP temperature 
> shows 41 C, and PA temperature is at 35 C  
> 
> This is not at objectionable at all, but made me wonder if this was a cause 
> for concern. 
> 
> Any ideas?
> 
> Tom W4KX

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Re: [Elecraft] Cooling Fans

[Steef PA2A]

Tom,

a few weeks ago the PA temperature of my K3 #1184 jumped between 32 and 
41 degrees Celsius during receive, and the fans went on and off. The 
problem went away after dismantling the K3 completely for another 
problem and the fan/temp problem has vanished. Maybe some loose 
connector had caused the problem. Monitoring the PA temp can be the 
first step to solve the problem.


73s Steef PA2A


From: Tom Doligalski 
To: Elecraft Reflector 
Subject: [Elecraft] Cooling Fans

I am the original owner of K3/100 #969, which still works great.

I?ve noticed that recently the cooling fan comes on occasionally even 
if the radio is on, but not in use >>(volume down, no transmitting). 
FP temperature shows 41 C, and PA temperature is at 35 C


This is not at objectionable at all, but made me wonder if this was a 
cause for concern.


Any ideas?

Tom W4KX

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Re: [Elecraft] Cooling Fans

[Mike Harris via Elecraft]

Hi,

FWIW.

Test conditions measured under the K3 DISP menu:

14.1V
1.38A Sub RX on
PA 32C
FP 40C

PA fans off
PA fans on/off at 36C/35C

Room temp 22C

K3 FP and PA temp sensors calibrated against a laboratory thermometer 
adjacent to the K3.


Never really noticed when the PA fans come on in idle conditions due to 
PC fan noise.


Regards,

Mike VP8NO

On 19/07/2020 12:15, John Simmons wrote:
> Tom,
>
> Interesting post. I thought this was the case with my K3 also, but i 
figured out later that it was the fan in my power supply instead. Poor 
hearing!

>
> -de John NI0K
>
> Tom Doligalski via Elecraft wrote on 7/19/2020 8:41 AM:
>> I am the original owner of K3/100 #969, which still works great.
>>
>> I’ve noticed that recently the cooling fan comes on occasionally 
even if the radio is on, but not in use (volume down, no transmitting). 
FP temperature shows 41 C, and PA temperature is at 35 C

>>
>> This is not at objectionable at all, but made me wonder if this was 
a cause for concern.

>>
>> Any ideas?
>>
>> Tom W4KX

On 19/07/2020 12:15, John Simmons wrote:

Tom,

Interesting post. I thought this was the case with my K3 also, but i 
figured out later that it was the fan in my power supply instead. Poor 
hearing!


-de John NI0K

Tom Doligalski via Elecraft wrote on 7/19/2020 8:41 AM:

I am the original owner of K3/100 #969, which still works great.

I’ve noticed that recently the cooling fan comes on occasionally even 
if the radio is on, but not in use (volume down, no transmitting). FP 
temperature shows 41 C, and PA temperature is at 35 C


This is not at objectionable at all, but made me wonder if this was a 
cause for concern.


Any ideas?

Tom W4KX

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Re: [Elecraft] Cooling Fans

[John Simmons]

Tom,

Interesting post. I thought this was the case with my K3 also, but i 
figured out later that it was the fan in my power supply instead. Poor 
hearing!


-de John NI0K

Tom Doligalski via Elecraft wrote on 7/19/2020 8:41 AM:

I am the original owner of K3/100 #969, which still works great.

I’ve noticed that recently the cooling fan comes on occasionally even if the 
radio is on, but not in use (volume down, no transmitting). FP temperature 
shows 41 C, and PA temperature is at 35 C

This is not at objectionable at all, but made me wonder if this was a cause for 
concern.

Any ideas?

Tom W4KX

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[Elecraft] Cooling Fans

[Tom Doligalski via Elecraft]

I am the original owner of K3/100 #969, which still works great. 

I’ve noticed that recently the cooling fan comes on occasionally even if the 
radio is on, but not in use (volume down, no transmitting). FP temperature 
shows 41 C, and PA temperature is at 35 C  

This is not at objectionable at all, but made me wonder if this was a cause for 
concern. 

Any ideas?

Tom W4KX

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[Elecraft] Cooling Fans

[David Robertson]

Ref. the message below:


I have never had any fan noise from my K3 that I could hear except when running 
a long winded qso on PSK31. Then the noise was barely discernable. #938.

Either I am stone deaf or Elecraft have gone to cheaper fans.

Dave KD1NA


I Bill NZ0T Wrote
 As I'm not a very technical person I just used a couple of resistors in
 parallel to slow the fan down in my 4225.  I can't remember the values this
 early in the morning but it seems to be working just fine.  The supply does
 run a little warmer but not hot and the fan is no longer heard.
 
 Bill NZ0T


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Re: [Elecraft] Cooling Fans

[Eric Swartz - WA6HHQ, Elecraft]

They are talking about the fans on an external MFJ power supply. Not those on 
the K3 :-)

73,

Eric
_..._
-Original Message-
From: David Robertson [EMAIL PROTECTED]
Date: Thursday, Aug 7, 2008 8:36 pm
Subject: [Elecraft] Cooling Fans
To: Elecraft elecraft@mailman.qth.net

Ref. the message below:


I have never had any fan noise from my K3 that I could hear except when running 
a long winded qso on PSK31. Then the noise was barely discernable. #938.

Either I am stone deaf or Elecraft have gone to cheaper fans.

Dave KD1NA


I Bill NZ0T Wrote
 As I'm not a very technical person I just used a couple of resistors in
 parallel to slow the fan down in my 4225.  I can't remember the values this
 early in the morning but it seems to be working just fine.  The supply does
 run a little warmer but not hot and the fan is no longer heard.
 
 Bill NZ0T



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Re: [Elecraft] Cooling Fans

[Brett Howard]

Usually the quieter fans are the more expensive ones...

On Thu, 2008-08-07 at 23:36 -0400, David Robertson wrote:
 Ref. the message below:
 
 
 I have never had any fan noise from my K3 that I could hear except when 
 running a long winded qso on PSK31. Then the noise was barely discernable. 
 #938.
 
 Either I am stone deaf or Elecraft have gone to cheaper fans.
 
 Dave KD1NA
 
 
 I Bill NZ0T Wrote
  As I'm not a very technical person I just used a couple of resistors in
  parallel to slow the fan down in my 4225.  I can't remember the values this
  early in the morning but it seems to be working just fine.  The supply does
  run a little warmer but not hot and the fan is no longer heard.
  
  Bill NZ0T
 
 
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Re: [Elecraft] Cooling Fans

[W7TEA]

I have to say that I expected the fans to be whisper quiet from all the
favorable posts I'd read before receiving my K3. My previous history is with
rigs having external cooling fins and no fans, so I'm probably spoiled
regarding fan noise.  As much as I do love the K3, I hear the fans kick in
when I have headphones on.  This happens after a fairly short CW qso at
100w.  The rig has been checked out at the factory, so I guess it re-affirms
the notion that everyone's ears are different.  

Gary W7TEA
#1001



David Robertson-6 wrote:
 
 Ref. the message below:
 
 
 I have never had any fan noise from my K3 that I could hear except when
 running a long winded qso on PSK31. Then the noise was barely discernable.
 #938.
 
 Either I am stone deaf or Elecraft have gone to cheaper fans.
 
 Dave KD1NA
 
 
 I Bill NZ0T Wrote
 As I'm not a very technical person I just used a couple of resistors in
 parallel to slow the fan down in my 4225.  I can't remember the values
 this
 early in the morning but it seems to be working just fine.  The supply
 does
 run a little warmer but not hot and the fan is no longer heard.
 
 Bill NZ0T
 
 
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 Help: http://mailman.qth.net/subscribers.htm
 Elecraft web page: http://www.elecraft.com
 
 

-- 
View this message in context: 
http://n2.nabble.com/Cooling-Fans-tp679932p679978.html
Sent from the Elecraft mailing list archive at Nabble.com.

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Re: [Elecraft] Cooling fans

[Chris Kantarjiev]

I don't have a K2 (yet), but I have a fair bit of experience with
trying to cool computer cabinets. 

You can get a wide variety of 'box' fans, that vary greatly
in how much noise they make and how much air they draw. I'm 
very fond of the ones that Antec sells - they cost a little
more, but have a very good airflow/noise ratio.

One model that might be of interest to the K2 (and similar)
users is the SmartCool line

http://www.antec.com/us/productDetails.php?ProdID=75008

which has a builtin thermistor and varies the speed by the exhaust
air temperature. They are also offering a variant that has the
thermistor on a separate mount, so you could have it cool
based on the temperature of the final output stage.

73 de chris K6DBG
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[Elecraft] Cooling fans

[R. Kevin Stover]

Thanks to all for the input

When I build computers I also pay attention to the thermodynamics and 
air flow inside the case. The fan on the CPU is pulling air through the 
heat sink and away from the motherboard and the hot air is expelled out 
the back or top of the case and cold air is drawn in at the bottom front.


I'm going to place them flat, up front right and back left to not cover 
the speaker. To fasten them I thought I'd use some very small pieces of 
double sided foam tape on each corner of each fan, just to keep them 
from sliding around.


Thanks again.


--
R. Kevin Stover ACØH

K2/100 #4684

Reclaim Your Inbox!
http://www.mozilla.org/products/thunderbird

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Re: [Elecraft] Cooling fans

[Jack Brindle]

Kevin;

You may not want to use foam tape. The heat's effect on the tape's  
glue should create quite a mess and eventually eliminate the  
stickiness of the tape. It would be interesting to know what other  
folks have done to keep the fans in place.


On Oct 30, 2005, at 6:25 AM, R. Kevin Stover wrote:

I'm going to place them flat, up front right and back left to not  
cover the speaker. To fasten them I thought I'd use some very small  
pieces of double sided foam tape on each corner of each fan, just  
to keep them from sliding around.




- Jack Brindle, W6FB
 
-



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RE: [Elecraft] Cooling fans

[Ron D'Eau Claire]

When I was experimenting with a box fan on top of the KPA100 heat sink, I
simply affixed four soft plastic feet to the corners. The kind one finds at
the hardware store to protect table tops, etc. 

They had enough traction to keep the fan in place on top of the fins without
any other adhesive, even with the K2 elevated at an angle on the bail. Of
course there was a small gap between the bottom of the fan and the fins, but
I had the air blowing down onto the fins instead of up. I positioned the
3-inch fan a couple of inches from  the forward edge, and there was no
discernable flow from the top fan that far away to interfere with the air
exiting the K2. 

I quit using it for two reasons: 

1) I HATE the sound of fans blowing. It's one of the most obnoxious sounds I
know. It's something that's almost not noticed while they're running, but it
feels like someone just took a huge weight off of me when they finally shut
up. Yes, that whizzer on the back of the K2/100 is real irritating to me
G, but at least it goes off after a bit. 

2) The fan wasn't needed, even after my longest, long-winded CW rag chew at
100 watts. 

Ron AC7AC

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Re: [Elecraft] Cooling fans

[Tony Morgan]

I use four desk drawer bumper pads. They are sticky on one side to 
mount to the fan, round and about 3/8 diameter with enough friction to 
keep the fan in place.

Works for me.

Tony W7GO

Jack Brindle wrote:

 It would be interesting to know what other  folks have done to keep 
the fans in place.




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Re: [Elecraft] Cooling fans

[Vic K2VCO]

Jack Brindle wrote:

Kevin;

You may not want to use foam tape. The heat's effect on the tape's  glue 
should create quite a mess and eventually eliminate the  stickiness of 
the tape. It would be interesting to know what other  folks have done to 
keep the fans in place.


I'm using a 3 fan on the right side of the heatsink (it's only needed 
there, right over the finals).  Mine pulls air up.  I put several diodes 
in series with the 12v supply to get a speed that would move enough air 
to be effective without making too much noise.  With the fan, it just 
does not ever get very hot!  I've been using double-sided tape for about 
a year with no problem.


--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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Re: [Elecraft] Cooling fans

[Jeff Stai]

At 09:28 AM 10/30/2005, Jack Brindle wrote:
It would be interesting to know what other  
folks have done to keep the fans in place.

I took two small rectangles of cardboard, punched a hole at one end, 
and secured them to the back of the K2 using the chassis screws.

The 12V 3 fans are lashed together using cable zip-ties and are 
simply laid on top, blowing down.

With the K2 tilted up (necessary for me) the fans slide down and rest 
against the cardboard stops. I suppose you could use metal stops for a 
more elegant look, but the two fans sitting on top make that seem pointless.

Using the fans I can run full tilt RTTY without worry.

cheers  73 - jeff wk6i


--
Jeff Stai   [EMAIL PROTECTED]
Twisted Oak Winery  http://www.twistedoak.com/


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[Elecraft] Cooling fans

[R. Kevin Stover]

Hello all.

I'm getting my K2/100 ready for sweeps and have decided to add some aux
cooling.
I have a couple of 3 computer case fans and was wondering from those
who've done the same about placement and whether blow the air onto the
heatsink or suck it through.

Thanks for your input.

R. Kevin Stover
AC0H
K2/100 # 4684.

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Re: [Elecraft] Cooling fans

[Jim Wiley]

Kevin -

It has been my experience that blowing air onto a heat sink is usually 
more effective than sucking  air.   If the heat sink is carefully 
shrouded and the incoming airflow is properly controlled, then either 
method is supposed to be effective.  However, for uncontrolled or casual 
situations where you are simply placing the fan on or near the heat sink 
to be cooled, blowing (hopefully cooler) air onto the heat sink fins is 
much more effective in lowering the temperature of the heat sink.   The 
reason for this is that the outlet of a fan has a well defined airflow 
that can be easily directed to where it is needed, whereas the inlet 
side of the fan will gather air from wherever it can, some or even most 
of which may not be from the heat sink.  Good luck in the contest.



- Jim, KL7CC



R. Kevin Stover wrote:


Hello all.

I'm getting my K2/100 ready for sweeps and have decided to add some aux

 


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RE: [Elecraft] Cooling fans

[Don Wilhelm]

Kevin,

The easiest solution is to simply lay the fan (horizontally) across the heat
sink fins.  Suck the hot air away from the heat sink, that way it works in
tandem with the internal fan rather than fighting the internal fan
airstream.

73,
Don W3FPR

 -Original Message-

 I'm getting my K2/100 ready for sweeps and have decided to add some aux
 cooling.
 I have a couple of 3 computer case fans and was wondering from those
 who've done the same about placement and whether blow the air onto the
 heatsink or suck it through.

 Thanks for your input.

 R. Kevin Stover
 AC0H
 K2/100 # 4684.



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RE: [Elecraft] Cooling fans

[Ron D'Eau Claire]

Also sure you don't have anything blocking the fins at the *front* of the
K2. The air blown in the back by the little fan comes out between the fins
where they reach the plate at the front of the KPA100. I've found that a lot
of people don't realize the gaps are there to let the air escape. 

For what it's worth, I helped do the thermal testing of John's PLL
temperature compensation mod (that's now built into current K2's). To do
that I hammered my K2/100 with a great many high-duty-cycle transmit
periods into a large dummy load while monitoring the internal temperature.
Many times the internal air temperature got up to 50C or 60C and the KPA100
heat sink was too hot to leave my hand on it very long. Absolutely no
deleterious effects were noted then or later. (Still have the same finals
too G). 

That rig is designed with a large margin of safety. 

Ron AC7AC


-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Don Wilhelm
Sent: Saturday, October 29, 2005 12:19 PM
To: R. Kevin Stover; Elecraft mailing list
Subject: RE: [Elecraft] Cooling fans


Kevin,

The easiest solution is to simply lay the fan (horizontally) across the heat
sink fins.  Suck the hot air away from the heat sink, that way it works in
tandem with the internal fan rather than fighting the internal fan
airstream.

73,
Don W3FPR

 -Original Message-

 I'm getting my K2/100 ready for sweeps and have decided to add some 
 aux cooling. I have a couple of 3 computer case fans and was 
 wondering from those who've done the same about placement and whether 
 blow the air onto the heatsink or suck it through.

 Thanks for your input.

 R. Kevin Stover
 AC0H
 K2/100 # 4684.



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Re: [Elecraft] Cooling fans

[Ken K7ZUM]

Ten-Tec has a very nice model 310 cooling fan for the Orion,Omni,Corsair
series radios, that fits very nicely on the top of the K2/100, hangs a
little
bit off the rear, and if you use the tilt bail on the K2, you can use a
rubber
band to temp hold it on, have used it this way many times, works well

73 de K7ZUM
Ken in GresHAM  Ore





 Kevin,

 The easiest solution is to simply lay the fan (horizontally) across the
heat
 sink fins.  Suck the hot air away from the heat sink, that way it works in
 tandem with the internal fan rather than fighting the internal fan
 airstream.

 73,
 Don W3FPR

  -Original Message-
 
  I'm getting my K2/100 ready for sweeps and have decided to add some aux
  cooling.
  I have a couple of 3 computer case fans and was wondering from those
  who've done the same about placement and whether blow the air onto the
  heatsink or suck it through.
 
  Thanks for your input.
 
  R. Kevin Stover
  AC0H
  K2/100 # 4684.
 
 

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Re: [Elecraft] Cooling fans

[John, KI6WX]

Kevin;
For some of my K2 power tests, I've placed a single 12V fan on the heat sink 
with 6-32 screws through the fan mounting holes to hold the fan about an 
inch above the heat sink.  The fan blows air down onto the top of the heat 
sink.  With that combination, I can run key down full power for a half-hour 
without excessive heating on the output transistors.

-John
KI6WX


Hello all.

I'm getting my K2/100 ready for sweeps and have decided to add some aux
cooling.
I have a couple of 3 computer case fans and was wondering from those
who've done the same about placement and whether blow the air onto the
heatsink or suck it through.

Thanks for your input.

R. Kevin Stover
AC0H
K2/100 # 4684.




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Re: [Elecraft] Cooling fans

[Mike Harris]

G'day,

| sink fins.  Suck the hot air away from the heat sink, that way it works 
in
| tandem with the internal fan rather than fighting the internal fan
| airstream.

The air stream from the internal fan flows into the K2 under the KPA100 
heatsink and emerges from the front.  That way it keeps much of the heat 
out of the box.

I have used a 3 inch fan sitting on the heatsink near the front propped up 
at 45 degrees and blowing to onto the area where the PA's are fitted 
underneath.  When I was doing some long run (12 hour) QRSS tests at 40W 
output the heatsink ran cool and the KPA fan didn't even come on.

Regards,

Mike VP8NO


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RE: [Elecraft] Cooling fans

[Don Wilhelm]

 -Original Message-

 The air stream from the internal fan flows into the K2 under the KPA100
 heatsink and emerges from the front.  That way it keeps much of the heat
 out of the box.

That is why I recommend pulling the air upward from the heat sink - so it
will help pull the air from inside the KPA100 as well - in the same
direction as the internal fan moves the air.  The ideal in my opinion is to
have just enough external fan that the amount of time the internal fan runs
is substantially reduced, but will still run with extended transmit periods
(like RTTY or PSK31 operation).  Doing things that way, it is mandatory that
I not buck the normal air flow of the internal fan.

For purposes of cooling a heat sink, it is just as effective to pull the hot
air away from it then to concentrate an air stream to blow onto it.  As an
added benefit, it also pulls away any dust that may be in the air rather
than causing it to load up on the heat sink and reduce the cooling
effectiveness.

A 12 volt auxiliary fan can be slowed down to about half speed by the
addition of a series resistor, and will likely stay in place with no
fasteners unless you have the KPA100 in a vibration prone environment.  A
slower fan will be much more quiet than one running at high speed and will
be quite effective.  The heat sink may get quite warm to the touch but it
should not be so hot that you cannot hold your hand on it.

73,
Don W3FPR

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