K2 #6665 Build

Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Day 8

Day 2

The CONTROL BOARD is done in about 6 hrs.

Day 3

The Front Panel (FP) is done in about 7 hrs.

Building notes:

You're better off soldering the LCD/difuser from the back of the board even if the pins do not stick out all the way. The solder will run down through the plated thru-holes. Just make sure you do see SOME of the pin (more the better) in the hole. As you melt the solder, and remove the iron tip you'll notice a little divot appear above the hole.. that's formed because the solder ran down into the plated thru hole. Leave it. Don't fill more solder. Check the front side of the board and notice the nice minimal fillet of solder around the pin.

The ground loops soldered on left and right sides of the FP? They are meant to stick out on the back side. The instructions are confusing, but if you remember that the Q1 and Q2 are installed with no more than 0.125" leads off the top side, you'll realize as I did that the 0.750" (!!) tall ground loops must protrude from the backside of the board. Maybe this was obvious to you.. Nevermind.

There's gotta be a better way to bend the leads of a IC. I can visualze a little clamp/vise that has a block of wood/plastic that the IC sits on. The pins hanging over the side like so many legs hanging over the edge in a swimming pool. Then a vise small enough to squeeze the pins from both sides, but not further than the block width protecting the pins from being smushed over... A picture here would be better. I found that adjusting the pins the riskier move given that they are probably more dificult to replace than regular components (I meant the IC that has firmware).

Pictures:


K2 All board built so far: Control and FP

K2 FP Before starting assembly


K2 FP after build top side


K2 after build top side pic 2


K2 FP after build bottom side

FP and Front Cover.

Be careful where you put the green filter. Do not cover up the screw hole for the 2-56 stainless screws for the bezel.

Decoder wirewrap


Decoder before soldering. See wirewrap around each cut pin.

Day 4

Getting the RF board further along. Here are the pictures of making the jig for putting the leads on the PLL board:
PLL Board and Mr. Lego with his radio

The RFC13, RFC15 comparison. There is no 'subminature' RFC15 in the kit so use the other 100uH solenoidal RFC. Body color/size is not important.
Comparing two different RFC body types/colors. The tan is already soldered into RFC13 location. The RFC15 (4 qty) is resting on top for size/color comparison. I used the brown RFC for RFC15 (100uH) on the underside connection RFC15.

Day 5

The RF Board with half the torroids wound and installed. Xtals X7-X11 installed and grounded.

Day 6

Well, the K2 is built. I finished the RF Board, wound the remaining toroids and finished the PA and tuning sections. The Part 3 alignment and configuration went well and I was able to test it to spec.

Day 6

After making the basic K2/10, I built the option KSB2 (SSB option) and installed that also.

The toroid winding is very simple there, except for the fact that the two 1/2" toroids on the KSB2 are transformers and the alignment of the pins and toroid alignment of where the turns come off the toroid require a bit of work to setup and place on the board. Pictures later.

The real absurdity was the 22 turns on the 3/8" little toriods that go on the KSB2 daughter board.

Day 7

I did not have the spare 5.6k ohm resistor to put on the back of the FP board for the Elecraft MH-2 mic. I'm not sure why they didn't ship a 5.6k ohm resistor in the kit. No bother, I picked one up locally.

First SSB contact was on 10m.

Anyway, I wrapped it all up and have it working on the multi-band antenna.

Day 8

Interesting email from a fellow K2 Builder made me look at the VCO data on my rig compared to Appendix B.
Band     Edge                   K2 6665    Page B.1        Diff     % Diff
80m      (3500kHz)              8413.64        8415        1.36       0.02
40m      (7000kHz)             11914.22       11915        0.78       0.01
30m      (10000kHz)            14913.78       14915        1.22       0.01
20m      (14000kHz)            18913.75       18915        1.25       0.01
17m      (18000kHz)            22913.75       22915        1.25       0.01
15m      (21000kHz)            16086.16       16085        1.16       0.01
12m      (24800kHz)            19886.28       19975       88.72       0.44
10m      (28000kHz)            23086.28       23085        1.28       0.01
I'm curious about the 12m result... More investigations are needed!