[K2] K2/100 - where does all the hot air go?

[Stephen Prior]

I have the 100W amp mounted in an EC2 enclosure, all working great now, no
small thanks to Don!

I have a question.  The little fan on the back seems to push air into the
unit, yet there is no obvious exit for it.  Or am I missing something?
Almost seems like I need an automatic vent popping up at the front (that
little panel could lift) like the vent on the back of a Porsche!  Perhaps
replacing that little panel with a perforated one would help?

I'm a little surprised at how quickly the fan comes on (on cw, I haven't
used ssb yet), and also quite taken aback by its noise!

73 Stephen G4SJP



_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Darwin, Keith]

Where does all the hot air go?

Why into the mic, of course

LOL!

Actually, when the KPA is mounted in the rig, there is space along the
front of the heat sink, right where it meets the stubby little front
panel.  Probably the same in the EC2.

Yes, the fan (whizzer!) is loud and annoying.  I have a quiet muffin fan
I set on top of my heat sink to keep it cool and prevent the little
whizzer from coming on.

- Keith N1AS -
- K2 5411.ssb.100 -
- K3 Wave 3 -
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Joe Malloy]

Hi, gang, I need your help.  I just received a new MH2 mike from
Elecraft and intend it for eventual use on my third round K3 order.  In
the meantime, I modified my K2 to use it -- the sheet included with the
mike provided instructions for doing so and I added the resistor across
pins 1 and 6 of the mike socket and use the header pins they provided.
All went tickety-boo.  I used to use an old Icom hand mic which worked
very well but I was looking forward to being all Elecraft (I have an
Elecraft Hexkey, too!)

Well, darn if the thing is giving me trouble: it acts as if there's RF
in the system but the mike socket is grounded and it even acts that way
at low power; my watt meter shows approximately 40 watts of power when
the mike key is depressed on LSB but -- get this -- no power is shown
when it's on USB where it seems to work fine!

What should I check?  Help!

Thanks...

73,

Joe, W2RBA


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Don Wilhelm-4]

Stephen,

The air exits just behind the front plate - through the fins of the heat
sink.  There is lots of exit area, no need to worry.

As far as just how fast the fan comes on, that depends on the
temperature (of the heat sink at the PA transistor locations).  CAL TPA
must be set in the menu should be set correctly, and set the FAN
parameter of the PA ON menu item to NORMAL (tap DISPLAY to toggle the
fan settings).

Turning the power down will reduce the heating and delay the fan turn-on
time <G>.

73,
Don W3FPR

Stephen Prior wrote:

> I have the 100W amp mounted in an EC2 enclosure, all working great now, no
> small thanks to Don!
>
> I have a question.  The little fan on the back seems to push air into the
> unit, yet there is no obvious exit for it.  Or am I missing something?
> Almost seems like I need an automatic vent popping up at the front (that
> little panel could lift) like the vent on the back of a Porsche!  Perhaps
> replacing that little panel with a perforated one would help?
>
> I'm a little surprised at how quickly the fan comes on (on cw, I haven't
> used ssb yet), and also quite taken aback by its noise!
>
> 73 Stephen G4SJP
>
>
>  

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Stephen Prior]

On 16/10/07 20:55, "Darwin, Keith" <[hidden email]> wrote:

> Where does all the hot air go?
>
> Why into the mic, of course
>
> LOL!
>
I should have expected that!  In my defence of course, I can add that
although I have the mic plugged in, it hasn't been used yet!

Now that I have been prompted to look at it more closely, I can see where
the air can escape, as you say on the edge of the heatsink.  I think I shall
go look on eBay for a quiet fan to sit on top as you have done.  I'm using
headphones 99% of the time, and I can even hear the noise of that little fan
through those!  It's rather like the Jack Russell dog we have here, small
and noisy!  Maybe I should be using the noise cancelling Sennheisers I
bought for our trip to NZ this year, trouble is I hate to feel excluded from
the sounds of the outside world (I might miss the offer of a coffee or
something!).

Thanks for the steer

73 Stephen G4SJP



_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Don Wilhelm-4]

Joe,

I am not certain why the Elecraft mike would have that kind of problem
and not the Icom mic.  I have trouble believing it has anything to do
with the particular mike.

Get out the computer and Spectrogram (or similar tool) and check the
position of the IF filter passband for both LSB and USB when in the FL1
filter position.  If you have the 2.4 kHz wide SSB filter center the
passband between Spectrogram markers set at 300 and 2600 Hz, if you have
the older 2.1 kHz filter, use 300 and 2300 Hz, and if you have the wide
2.6 kHz filter use 300 and 2900 Hz markers.  Note that the lower marker
does not change - it should always be 300 Hz.

Once the passband positions are correct, do the carrier balance
adjustment.  You can do it as instructed in the manual, or if you have a
means of measuring small RF voltages (like with a 'scope), you can plug
in a key (no mic connected), set for LSB then hold the dot side of the
paddles (DOT and PTT are the same line inside the K2), and adjust the
pot for minimum RF voltage.  Check USB and if necessary, tweak the
balance pot for a compromise between LSB and USB.

After those adjustments are complete, check the mic operation again.  If
you still have trouble, you may want to check for 'RF in the shack' (but
I would think that should be a problem with both sidebands).

73,
Don W3FPR


jmalloy wrote:

> Hi, gang, I need your help.  I just received a new MH2 mike from
> Elecraft and intend it for eventual use on my third round K3 order.  
> In the meantime, I modified my K2 to use it -- the sheet included with
> the mike provided instructions for doing so and I added the resistor
> across pins 1 and 6 of the mike socket and use the header pins they
> provided. All went tickety-boo.  I used to use an old Icom hand mic
> which worked very well but I was looking forward to being all Elecraft
> (I have an Elecraft Hexkey, too!)
>
> Well, darn if the thing is giving me trouble: it acts as if there's RF
> in the system but the mike socket is grounded and it even acts that
> way at low power; my watt meter shows approximately 40 watts of power
> when the mike key is depressed on LSB but -- get this -- no power is
> shown when it's on USB where it seems to work fine!
>
> What should I check?  Help!
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com