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..
Friday
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.
Saturday
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!
Sunday
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!
Monday
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.
Wednesday
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.
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.
Thursday
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!
Friday
Completed a first run through of the RX alignment and have now heard a few CW signals!
Saturday
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.
Sunday
Installed the PA. Power up tests OK. No further sign of the LED segment problem.
Monday
Completed assembly. Tested the PA. Planning the first QSO for KX1 Serial 1854 at SADARS tommorow.
Tuesday
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
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.