[Elecraft] KX1 ATU - Alignment & Test

[Don Wilhelm]

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
>   
>