[Elecraft] K1 filter board tuning with KAT1

[Mike Morrow]

>> I have a K1 in which I just swaped the 17M parts for 20M parts.  Now the
>> filter board needs to be aligned.  Question is how does one get around the
>> KAT to access the filter board?

>Just remove the tuner board and install the jumper in the tuner connector, 
>do the alignment and reinstall the tuner


Well...it'll take a little more than that.  See step (3) and (7) below.

(1)  Install the filter board to be aligned.
(2)  Do NOT install the KAT1.
(3)  Change the pin jumper block on P3 in the right rear corner of the RF board from pin 2 and 3 (KAT1) to pin 1 to 2 (K1 only).  The KAT1 normally supplies power output info to the front panel MPU.  When the KAT1 is missing, the power signal comes from a resistor/diode circuit which is connected to RF output only when P3 pin 2 is connected to pin 3.
(4)  Install a short solid wire from pin 2 to pin 10 on J2 on the filter board.  This makes up for the KAT1 not being present in the RF output path.
(5)  Align the filter board per instructions.
(6)  When alignment is complete, remove the jumper installed in (4) above.
(7)  Change the jumper block on P3 in (3) above to connect pin 2 and 3 (KAT1) position.
(8)  Install the KAT1 and you're done.

I would highly recommend keeping the KAT1.  It is a really really nice feature.  The designers of the Yaesu FT-817 were NOT smart enough to recognize how valuable an internal auto tuner could be, so it's just a gimmick QRP rig.  If you want to use an external tuner, you can set the KAT1 for bypass from the menu and still take advantage of the better power indication and the SWR indication that you will loose if you remove the KAT1.

And if you don't have a four-band filter board, get one!  Then you can rebuild your two-band board for whatever additional bands you want.

73,
Mike / KK5F