K2 Update - Final Thoughts

After completing the K2 and the KPA100, I noticed a problem with the rig. When the rig heated up, there were receiver "dead zones" every 5 KHz. In addition, I could not successfully perform a CAL PLL function. The CAL PLL would fail with an INFO 232 code. (CAL PLL is a VFO linearization process.)

I discovered the problem in the fall of 2002, but since the ham shack is fairly cool during fall and winter, I put off completing my troubleshooting until spring. Well, spring 2003 came along, and I was finally ready to work on the problem again.

I found that the amplitudes of the PLL reference oscillator and the VCO were in spec. While watching the VCO's frequency, I noticed that during a receive "dead zone" the control voltage from the PLL chip was around zero, forcing the VCO frequency to be out of range. It wasn't clear to me at this point if the problem were the PLL chip or the reference oscillator. The suggested steps from Elecraft support was to start rebuilding the PLL reference oscillator since a bad PLL chip was unlikely.

At this point, I decided that I didn't want to do a lot of desoldering without knowing where the problem really was. So, I boxed up the K2 and sent it off to Elecraft for repair. It turns out the problem was a bad PLL chip. Because I had waited until spring to resolve the problem, the K2 was out of warranty, and I paid for the repair.

The repair work by Elecraft was excellent. Not only was the problem fixed, but some mods were installed and some new items, like a better grounded KPA100 shield, were added. A complete alignment and checkout was also performed.

So, my analysis of the Elecraft kits is still pretty much the same as before. The kits are great, but I would rate them as definitely advanced kits. I enjoy my K2, but if I knew then what I know now, I would have passed on the kit building.

E-Mail: ham at tuxcat.com.