New Final for the K1

I have now waited more than two weeks for the 2SC1969 that I have ordered from El Supply. Since the Easter holidays are coming closer and closer and I want to have the K1 with me, I looked for another source. I found Brinck Elektronik who has a shop in Copenhagen city. I was lucky enough to get the last piece they had on stock. They can still order it for me later but it will cost twice as much.

I cleaned the holes on the K1 main board using my solder sucker. It was relatively easy by heating on one side and sucking on the other. After mounting the new final I have redone the resistance and voltage tests. All of them were all right and the transmitter alignment test were good, too. Using 13 VDC the current consumption is just below 1A @ 5W out.

Now, let’s see whether I can nuke this final too, by hooking it up to the ATX-1080…

Well, I hooked up the FT-817 to the ATX-1080 via the T1 and tuned up the T1 at 7.010 MHz. Then I switched to the K1 to try the transmitter there. I started out with 1 watts and it was all right, although the power supply tripped once in a while. Hmmm… I tried to listen to the transmitted signal and it was fine, too. Then when I increased the power level to 5 watts and transmitted for a while the K1 went out and died, drawing current (less than 2 amps). After that I couldn’t turn it on anymore.

Later on I found out that I was the stupid one, because somehow I put the T1 in bypass mode. Still, the SWR wasn’t so bad and I did also have a 1.5 amp fuse on the supply wire. The fuse survived! I must admit that at this stage I am rather confused… How on earth can this happen? Is the K1 really so fragile? If so, how on can one use it in the field with all sorts of random wires?

I don’t think I can do more before the Easter holidays, so the holidays will be without the K1 Cry