I have played some more with the filter board. I decided not to worry too much about it because the trimmers will be altered again during transmitter alignment, but here are the alignment results so far:
Conclusion on the Filter Alignment
I have tried to use my other dummy load on the FT-817. It did indeed reduce the signal strength in the K1 quite a lot. This may sound a bit strange but it is not. You know, the DL-1 dummy load kit from Elecraft is an open dummy load, meaning that it is not in an enclosure, thus the RF signal is radiated from it. My other dummy load, on the other hand, is built into a piece of cooling metal and looks much more radiation closed than the DL-1 does.
New Attempt on the Filter Alignments
Nice surprise as I came home from work today: The replacement FT37-61 core for the noise blanker has arrived! That was fast. I sent the email on the 2. or 3. got a reply on the 3. and received the new core on the 7. All the way from USA.
K1 Filter Board Alignments
I have hooked up the FT-817 to a dummy load in order to perform the receiver tests on the K1. The first tests consist of aligning the trimmer capacitors on the filter board. To begin with I used the DL-1 dummy load.
K1 VFO Checks
The VFO range check is perfect. Without needing to do any modifications, not even squeezing or sopreading the turns on L1, I have a VFO range between 2.993 MHz and 3.094 MHz. The VFO seems as stable as a VFO of this kind can get. There is a frequency shift of 1 kHz down if … Read more
My K1 is Alive!
Tonight I continued with the combined tests of the RF board (part 1), front panel board and filter board. All tests up to the VFO test are ok, including LED/LCD, error codes, sidetone generator, voltmeter, keyer and filter board relays. On the picture below you can see the very first thing K1 says, when no filter board is found.
Successful Filter Board Tests
After completing the assembly of the K1 filter board, I have done the resistance checks on the board. All checks tests passed perfectly 🙂 The next step will be to proceed with the tests of the RF board and then the combined tests and alignments of the RF + filter boards, which in fact is … Read more
Coils for the Filter Board
I have just finished mounting the coils onto the K1 filter board. It turned out that some transformers need their secondary to interleave with the primary, on the contrary to what I mentioned earlier. I guess it depends on the function of the transformer.
K1 Filter Board
I have finished mounting all parts on the filter board, except the inductors and plugs. I was surprised by how badly some of the capacitors fit in the holes. It is not quite what I am used to from Elecraft but it’s really no big deal. Maybe the capacitors don’t fit because the original ones … Read more
The K1 is Taking Shape
After mounting L2, T1 and T2 on the RF board, it was time to mount the side panels on the RF board and mate it with the assembled front panel board. This has to be done before the receiver alignments and it is really cool, because I can now see the K1 taking shape: