I started the K2 Build - Serial Number 7105 on March 15, 2011. Prior to March 15, I dedicated time to building a dedicated construction table shown below:
The procurement of necessary tools also became necessary - A Weller WES51 temperature controlled soldering iron, a digital multimeter that measures capacitance and an LED magnifier lamp. The K2 parts can be small and seeing the joint at 3X magnification is really very helpful. I started on March 15 at 8 PM and finished soldering the resistors in about 3 hours. The next day - On 3/16 I installed the potentiometer R1 and the shilded inductor L1 along with 6 resistor packs. Elapsed time is 6 hours over both days.
Started at 2100EDT and installed 35 fixed capacitors. This took some planning as the capacitance values are hard to read. I read the capacitance with 2 magnifying glasses and then laid out all the capacitors on a sheet of paper with labels. Then it was much easier to retrieve the capacitor as I went in sequence installing them on the PCBs. The leads were spread apart to hold them in place and leads clipped to about .5 inch. Ready to solder at 2248EDT. Also installed a pair of diodes. Elapsed time - 2 hours. Total build time so far 8 hours. Photo below.
I soldered the fixed capacitors from the March 20 effort and then proceeded to solder the electrolytic capacitors to the printed circuit board. These are the round capacitors in the photo below. Elapsed time 2 hours. Total build time - 12 hours.
Set up shop at the GE training center in Crotonville NY. I am here for two weeks on a training class for technology leaders and I was torn whether to bring the FT897D or to continue building. It was a wise choice to continue building as there is down time that I can dedicate to building. Well, the shop away from home -what does it look like? See below:
I have been able to solder in the transistors and the crystals along with the voltage regulator ICs. I then soldered in the 40 pin socket for the U6 micro-controller. Grounding the crystals tended to be a tricky but was able to put the jumper leads after a bit of twiddling.
Finished soldering all the ICs and the connectors to the control board. The main IC U6 was also pressed onto its socket. Shorting jumpers were also installed. The control is almost ready for resistance checks. Tomorrow I will install two capacitor jumpers and then the board will be ready for inspection and checkout for cold solder joints, solder bridges and unsoldered pins. Then the resistance check follows. Build time today is 6 hours. Total build time so far is 18 hours.
Alan Wilcox was kind enough to supply these reference photos for SN5373 for both the top and bottom of the control board. It was comforting to know how my board matched his.
Soldered he backside components - fixed and electrolytic capacitors and performed resistance checks. The resistance checks passed except for the following:
U6 PIN 29 Required Resistance to Ground 70-90k (Actual measured 74k momentary then steady 96k)
U6 pin 30 Required Resistance to Ground 70-90k (Actual measured 74k momentary then steady 96k)
Passed on the questions to Elecraft to see if this is OK. Total build time so far 21 hours.
Elecraft gave me the all-clear after receiving my e-mail. Elecraft is great with the turn-around time on any questions the builder may ask. I also ordered the KSB2 option (SSB board) which should be timely as I build the front panel board. I organized all the front panel parts in my clear plastic box organizer ready to start.
March 30 - April 2
The Front Panel and the Control Panel are both finished and passed their respective resistance checks. The RF board has been started and the 17 latching relays have been installed along with 3 electrolytic capacitors and 4 resistors. Phase 1 power-on testing is only a few days away and maybe complete as early as this weekend.
The RF Board construction continues - installed the high current diodes D10 and D12, power switch, headphone jack, DC input jack and and antenna jack. Incremental build time 2 hours. Total build time 30 hours.
Installed the main IC controller and the RF board to control board connectors. Passed all Phase 1 resistance checks. Incremental build time 2.is hours. Total build time is 32 hours.
Assembled the RF board, control board and front panel board together for the first time and performed the Phase 1 alignment checks. Built the diagnostic tools - frequency counter, RF probe and voltage probe. Set the AGC threshold at 3.8 Volts, aligned the S meter, performed the bar graph current test. All Phase 1 tests passed with flying colors. Total build time 34 hours.
May 10- May 11
Started soldering in the large list of resistors - took 8 hours total just for the first set of resistors.
Installed the thermistor board, diodes and transistors. Incremental build time is 5 hours. Total build time 47 hours.
May 13 - May 14
Installed more transistors and finished installing the capacitors. Installied the 6 pin and 8 pin ICs. I did not count the capcitors but there are about 70 eyeballing the list. Total build time 57 hours.
May 15 - May 20
Finished building the RF board ready for Phase 2 alignment. Passed all resistance checks. Total build time 67 hours.
Completed all Phase 2 alignment - thanks to Mike W5MFC lending me his MFJ259B which I used as a frequency counter for calibrating the 4 MHz oscillator. Passed all Voltage Controlled Oscillator tests, VCO alignment checks and BFO alignment. The VFO was linearized. The IF amplifier for the 40 meter band was aligned. Toal build time so far 70 hours.
Started the RF Board for the last and final phase. Finished adding the last resistors on the top of th board. Constructed a jig here which I also used for Phase 2 construction to hold the board underneath the magnifier.
The battery kit and auto-tuner kits arrived today. The connectors for the battery kit and auto-tuner got installed. With the exception of a couple of parts (a 120 microfarad monolithic capacitor which was missing from the kit and an RF choke) all the parts are installed on the RF board. I hope to be on the air this weekend. Total build time prior to final checkout - 80 hours.
July 2, 2011
I built a wooden case for the K2 to give it a distinctive look. All the modules have been installed - SSB, Audio Filter, Auto-tuner, 160m band, internal battery and noise blanker. I also put in a internal microphone adapter from unpcbs.com to allow connection of different microphones with matching bias resistors. Also I added a charging port to directly charge the battery using my smart charger instead of the power supply, similar to what Don Wilhelm of Elecraft suggested in his own site. The reverse polarity protection diode and the resistor does not allow a standard 13.8V power supply to charge the battery to its full potential.
September 7, 2011 - KPA100 Installed
It took a little history reconstruction. The KPA100 was sold to me by KF4BY and it was also built by him,
January 1, 2018
This K2 (now a K2/100 with a KAT100 - which I also built) shown next to the K1 in the photo below has been a steady and solid performer. In 2017 - I completed DXCC on 160m using this K2/100 as the exciter for my amp. In 2016, I had the power dialed back to 5 watts when I competed in the 2016 DX Marathon - placed 6th (missed 5th place by 1 QSO point) - also with this K2.