“Those who hear not the music, think the dancer mad”
Elecraft KX1 Construction
Elecraft KX1 Construction /P

Elecraft KX1 Build

Easter Holiday Construction /P

We planned to spend Easter at the cottage in Cromford. Last time we visited I started to miss the delights of melting solder so this time instead of watching TV or reading in the evenings I planned to try some construction /P.
The very complete Elecraft KX1 kit had been waiting patiently under my bench for several months and looked ideal as it required very little in the way of tools or equipment to build it. I packed it up along with an old camping table, a few tools, soldering iron and the essential magnifying desk light ready for our trip.

Thursday - Cromford

I have setup the camping table. Although small it provides a neat workspace by the window in an upstairs bedroom so I can see the trees and mill stream while soldering!

As the cottage is a bit cold in the evenings we camped out in the downstairs bedroom nearer the gas fire. Oh for central heating. Did not get much construction done as the local pub had a beer festival on..


Elecraft KX1
KX1 Evening Construction /P

KX1 Part 1 assembled. I have just done the first power on tests which look fine. Quite a way to go though.

The temporary workbench works well. Not much space is really needed and it means that everything is close to hand.

Nice and bright at the moment, so we will be off to get a few supplies and have a wander around the village, although I can't guarantee we won't visit the pub.


More testing..

1. Carefully remeasured everything, only the 6v is incorrect!
2. Posted to the Elecraft group.
3. Went out for a walk to the Barley Mow for lunch!
4. Got back and read various suggestions from the Elecraft group.
5. Removed U9.
6. Found that my handhelds PSU is 6 volts.. Handy!
7. Tested and wired up the 6 volt PSU to the U9 socket.
8. Tested the voltages.. All OK!
9. Then noticed C10 was missing - This cap is needed to stop the regulator oscillating...
10. Time for a large glass of red wine..
11. Fitted C10, reworked and refitted U9.
12. Tested the voltages.. All OK!

Phew that was a long way round. But construction is now back on track!


Elecraft KX1
KX1 Fault Finding /P

More construction, now up to page 40. Carefully wound and installed the L2 toroid; as soon has the solder had set I realised L2 should be on a yellow toroid not a grey one.. Time to go out again!


I have got to page 42. Then on to the relay checks - all OK. I switched off the rig then later I switched back on and plugged in my headphones for the sidetone test. 7 displays briefly; then just the single lower left most vertical LED segment flashes. I have tried a reset but as soon as the switches are released the same LED
segment still just flashes.


Back at home. Emailed Elecraft and they suggested a through check of the board paying particular attention to the joints on U1 - the microprocessor.

I have now very carefully checked the solder joints across the board, paying particular attention to the display and U1 (reflowing the joints and reseating U1) I also tripled checked the relays. I still get the same results. Relay clicks, 7 displays, then just the lefthand side vertical lower single LED segment flashes. Emailed Elecraft an update, in the meantime I might build the 30/80 board and auto ATU options.

“Time for a glass of red wine..”

Started building the auto ATU, great to have green and red wire for the transformer toroid; after the SoftRock it certainly makes things a lot easier.


Completed the Auto ATU.

Rechecked all the joints around the display with an eyeglass and then re soldered them. Powered up and still got the same display error.
Rechecked and re soldered RP5 and adjacent resistors; removed a tiny piece of debris with a toothbrush. Powered up OK!

Elecraft KX1 Complete
KX1 Complete


Completed a first run through of the RX alignment and have now heard a few CW signals!


Completed the last toroid. Installed the power output modification kit, which just consists of replacement resistors for R30 and R11. It would have saved some rework had this mod been installed as part of the main build.
Reviewed the quite extensive 30/80m modification. Decided to complete and fully test the KX1 prior to installing it.


Installed the PA. Power up tests OK. No further sign of the LED segment problem.


Completed assembly. Tested the PA. Planning the first QSO for KX1 Serial 1854 at SADARS tommorow.


Did not end up testing the KX1 at SADARS. But managed to sample a few beers at our local - The Our Mutual Friend.

Tuesday 15th April

With G0WAT on the key, KX1 1854 made it's first QSO on 20m using the clubs beam, contacting ER5GB in Moldova. Only the 30/80m module remains.

Sunday 27th April

Elecraft KX1 30/80M Module Close Up
30/80 Module Close Up

Finally completed and installed the 30/80M module. This required careful soldering and positioning to ensure a good fit and hopefully avoid shorts.
Powered up OK. Next step is to re peak the filters.