Elecraft KX1: Alignment and Test

I hit a snag while running through the testing stage of the build. On 20m, I could align the receiver as called for in the build instructions. All that was needed was to fire up my FT-450, connect it to a dummy load and wind back the power to 5W. Then, while listening to the KX1 with earbuds, send a signal via the FT-450 and peak two trimmers for maximum noise.

That was easily done.

Then what I needed to do was repeat the process for 40m. This was where I hit a snag. I couldn’t hear anything in the earbuds.

Time to start troubleshooting. I reheated all the solder connections, looked for solder bridges and anything else that might be wrong. I double checked the components but all seemed OK. So I shot off an email to Elecraft seeking advice.

Gary, AB7MY responded with a heap of good advice. I pulled out crystal X5 just to make sure I didn’t have any soldering problems but all seemed OK, so back in it went.

I could find nothing wrong so enlisted the help of Wallace, VK4CBW, who has some good test equipment (and sound knowledge). We ran though some basic checks first and then hooked up his oscilloscope and started signal tracing. Within minutes he found that I had soldered in one of the RF chokes (L4) into a wrong hole. I wondered how we would remove this as I had never been particularly good at using solder braid. But Wallace had a better idea, and good tools. He pulled out a desoldering vacuum machine and boy did this thing work! Did the job in no time at all and left beautifully clean holes.

Back in the shack I dug out a spare 2.2uH choke (luckily I had one in my spares cupboard), soldered it back in and proceeded to align the rig on 40m without further problems.

This little mistake was also causing the encoder Z1 to be very noisy when changing frequency. I would hear loud clicks in the earbuds. That has now gone too and changing frequency is now silently achieved.

So on now with the build …

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One thought on “Elecraft KX1: Alignment and Test

  1. Ah yes Grant, I suppose if you follow the instruction down to the letter all will be well. But if you make that one little mistake (as you did!) then the problems start. Luckily Elecraft have those times during the build that you can test what you have just completed. I have built their K1, K2, (and K2/100) and KAT100 ATU and luckily (written with crossed fingers and holding thumbs!) I didn’t have any problems.
    I had endless problems building a TenTec 1340 but the problem was not one of TenTec but my own making. Toroids – I never have had a problem winding them, but it took me a long time to learn to make a PROPER soldering joint on the toroid! But it is a live and learn experience and I await to hear how you get on with the building. Good Luck,
    Ian ZL2AIM

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