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KX1 ATU - Alignment & Test

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Burke Jones

KX1 ATU - Alignment & Test

Okay, I have assembled the KXAT1 ATU for the KX1. I got it installed into
the rig tonight and I am working on the "Alignment & Test" section on Page 7
of the manual.

I did preset R1 & R2 per the errata picture.

Everything went fine until I started adjusting C9 for the lowest possible
voltmeter reading. I have a MV scale on my DMM. The first problem I
noticed was that when I entered the TUNE mode, my display showed P0.0 with a
12.4V power supply. I adjusted C9 to give me .2 mv on my DMM - the lowest I
could get. When I canceled TUNE MODE it showed r1.0. I was running it into
my 50 ohm dummy load by the way.

Should the display show something other than P0.0? Sometimes it would
briefly show P0.1 - but on for a split second.

I could hear the signal being transmitted into the dummy load on another
receiver - so it is transmitting.

Any thoughts?

Burke Jones
N0HYD - Olathe, KS
http://www.n0hyd.com
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Don Wilhelm-4

Re: KX1 ATU - Alignment & Test

Burke,

First make certain D1 is oriented correctly. Can you verify that you
are actually getting 2 watts or more output? If so, please do that.
If you actually do have output, make the following measurements during
transmit:
1) Cathode of D1 - the voltage will depend on the transmit power
2) P3 pin 5 - the voltage should be about half of the voltage in 1)
above (depends on R1 setting)
3) KX1 U1 pin 2 - the voltage should be the same as in 2) above if all
connections are solid.

If those voltages are as I have indicated, then remove the KX1 board
from the enclosure and check the socketed firmware chip. Pin 2 should
be properly inserted into the socket, not sticking out to the side or
bent under.

If all looks good so far, solder a test point lead on the firmware chip
itself and bring it out to the end so you can measure the voltage
directly on the chip lead after putting the KX1 board back in the
enclosure. Make the check again and see if you have the same voltage at
the chip lead as you do at the bottom of the socket. If the voltage is
the same, you need to install a replacement firmware chip.

If you have proper voltage at one point, but not the next, there is a
bad connection between those two points.

73,
Don W3FPR

Burke Jones wrote:

> Okay, I have assembled the KXAT1 ATU for the KX1. I got it installed into
> the rig tonight and I am working on the "Alignment & Test" section on Page 7
> of the manual.
>
> I did preset R1 & R2 per the errata picture.
>
> Everything went fine until I started adjusting C9 for the lowest possible
> voltmeter reading. I have a MV scale on my DMM. The first problem I
> noticed was that when I entered the TUNE mode, my display showed P0.0 with a
> 12.4V power supply. I adjusted C9 to give me .2 mv on my DMM - the lowest I
> could get. When I canceled TUNE MODE it showed r1.0. I was running it into
> my 50 ohm dummy load by the way.
>
> Should the display show something other than P0.0? Sometimes it would
> briefly show P0.1 - but on for a split second.
>
> I could hear the signal being transmitted into the dummy load on another
> receiver - so it is transmitting.
>
> Any thoughts?
>
> Burke Jones
> N0HYD - Olathe, KS
> http://www.n0hyd.com
>
>

______________________________________________________________
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

Burke Jones

Re: KX1 ATU - Alignment & Test

I know this is an old thread, but I thought I would revisit it.

After a couple of months of "life" I was finally able to get back down to
the bench. I picked up the ATU and immediately noticed a big white
rectangle with no part. I had forgotten to install R5!

I don't know how many times I had looked at that board and not noticed it,
but last night it jumped right out and got me.

Now the display is showing power out, but not what it should be. It is
under a watt output on 40 and 20.

I will spend some more time tonight looking it over and be sure I have C9
properly set.

Anyway, I thought you would appreciate the update!

Burke
http://N0HYD.com <http://n0hyd.com/>

On Wed, Apr 15, 2009 at 8:46 AM, Don Wilhelm <[hidden email]> wrote:

> Burke,
>
> First make certain D1 is oriented correctly. Can you verify that you are
> actually getting 2 watts or more output? If so, please do that.
> If you actually do have output, make the following measurements during
> transmit:
> 1) Cathode of D1 - the voltage will depend on the transmit power
> 2) P3 pin 5 - the voltage should be about half of the voltage in 1) above
> (depends on R1 setting)
> 3) KX1 U1 pin 2 - the voltage should be the same as in 2) above if all
> connections are solid.
>
> If those voltages are as I have indicated, then remove the KX1 board from
> the enclosure and check the socketed firmware chip. Pin 2 should be
> properly inserted into the socket, not sticking out to the side or bent
> under.
>
> If all looks good so far, solder a test point lead on the firmware chip
> itself and bring it out to the end so you can measure the voltage directly
> on the chip lead after putting the KX1 board back in the enclosure. Make
> the check again and see if you have the same voltage at the chip lead as you
> do at the bottom of the socket. If the voltage is the same, you need to
> install a replacement firmware chip.
>
> If you have proper voltage at one point, but not the next, there is a bad
> connection between those two points.
>
> 73,
> Don W3FPR
>
>
>
> Burke Jones wrote:
>
>> Okay, I have assembled the KXAT1 ATU for the KX1. I got it installed into
>> the rig tonight and I am working on the "Alignment & Test" section on Page
>> 7
>> of the manual.
>>
>> I did preset R1 & R2 per the errata picture.
>>
>> Everything went fine until I started adjusting C9 for the lowest possible
>> voltmeter reading. I have a MV scale on my DMM. The first problem I
>> noticed was that when I entered the TUNE mode, my display showed P0.0 with
>> a
>> 12.4V power supply. I adjusted C9 to give me .2 mv on my DMM - the lowest
>> I
>> could get. When I canceled TUNE MODE it showed r1.0. I was running it
>> into
>> my 50 ohm dummy load by the way.
>>
>> Should the display show something other than P0.0? Sometimes it would
>> briefly show P0.1 - but on for a split second.
>>
>> I could hear the signal being transmitted into the dummy load on another
>> receiver - so it is transmitting.
>>
>> Any thoughts?
>>
>> Burke Jones
>> N0HYD - Olathe, KS
>> http://www.n0hyd.com
>>
>>
>

Don Wilhelm-4

Re: KX1 ATU - Alignment & Test

Burke,

Yes, do set C9 for the null as indicated in the manual. It makes a BIG
difference in both the forward and reverse (SWR) power readings. If the
KXAT1 does not show decent power out - in ATU CAL mode into a 50 ohm
dummy load, then remove the KXAT1 and install the jumper at J7, then
using a known accurate external wattmeter, tell us what the power output
on the base KX1 is for each band - ideally, power the KX1 from a 13.8
volt power supply - the reference data I have is based on that power
supply voltage, and lower voltages will result in lower power outputs.

73,
Don W3FPR

Burke Jones wrote:

> I know this is an old thread, but I thought I would revisit it.
>
> After a couple of months of "life" I was finally able to get back down to
> the bench. I picked up the ATU and immediately noticed a big white
> rectangle with no part. I had forgotten to install R5!
>
> I don't know how many times I had looked at that board and not noticed it,
> but last night it jumped right out and got me.
>
> Now the display is showing power out, but not what it should be. It is
> under a watt output on 40 and 20.
>
> I will spend some more time tonight looking it over and be sure I have C9
> properly set.
>
> Anyway, I thought you would appreciate the update!
>
> Burke
> http://N0HYD.com <http://n0hyd.com/>
>
>

Burke Jones

Re: KX1 ATU - Alignment & Test

It's ALL good! I used the milivolt setting on my DMM, and really fine tuned
C9 for the null which is really sharp. Now the power meter is reading
correctly, and I am good to go.

I will be heading to the deck tonight to toss up my end fed antenna, and
give it a whirl. My CW is pretty rusty - but if you are listening on 40
near the QRP calling freq - and have patience, I would love to work anyone
out there!

Don, thanks so much for all your help! The KX1 has been a really fun little
project, and I hope to build more Elecraft kits in the future.

Burke Jones
http://N0HYD.com <http://n0hyd.com/>

On Wed, Jul 8, 2009 at 6:01 PM, Don Wilhelm <[hidden email]> wrote:

> Burke,
>
> Yes, do set C9 for the null as indicated in the manual. It makes a BIG
> difference in both the forward and reverse (SWR) power readings. If the
> KXAT1 does not show decent power out - in ATU CAL mode into a 50 ohm dummy
> load, then remove the KXAT1 and install the jumper at J7, then using a known
> accurate external wattmeter, tell us what the power output on the base KX1
> is for each band - ideally, power the KX1 from a 13.8 volt power supply -
> the reference data I have is based on that power supply voltage, and lower
> voltages will result in lower power outputs.
>
> 73,
> Don W3FPR
>
> Burke Jones wrote:
>
>> I know this is an old thread, but I thought I would revisit it.
>>
>> After a couple of months of "life" I was finally able to get back down to
>> the bench. I picked up the ATU and immediately noticed a big white
>> rectangle with no part. I had forgotten to install R5!
>>
>> I don't know how many times I had looked at that board and not noticed it,
>> but last night it jumped right out and got me.
>>
>> Now the display is showing power out, but not what it should be. It is
>> under a watt output on 40 and 20.
>>
>> I will spend some more time tonight looking it over and be sure I have C9
>> properly set.
>>
>> Anyway, I thought you would appreciate the update!
>>
>> Burke
>> http://N0HYD.com <http://n0hyd.com/> <http://n0hyd.com/>
>>
>>
>