Excessive current drain on KAT2?


From: "Steve Uhrig" <Steve@swssec.com>
To: elecraft@qth.net

Once upon a midnight dreary, Rich Mulvey pondered, weak and weary:

Steve said first:
> > Last night I completed the ATU for my K2. 

> > However, I notice a lot of current being drawn now after installing the
> > KAT2. My receive current drain according to DISPLAY before was 240 mils.
> > Now with the tuner it is 440 mils. Wot gives?

Rich replied:
> I had exactly the same problem. As it turned out, when I installed
> R6, I installed it in the wrong holes... thus shorting it out ( even
> though the KAT2 still worked fine ). 

Steve again:
This was the problem. R6 (47 ohms) directly across the 6VDC line to 
ground. Be careful here; R6 looks like it belongs in those holes, and the 
spacing is perfect. But the proper location for R6 is in another set of 
holes immediately adjacent. Since the two KAT2 boards are assembled 
already by the time you are told to finally install R6, it is difficult 
to see the R6 outline silk screened on the component side of the board. 

A free for nothing fix would be to screen R6 on the foil side of the 
board also.

I put R6 where it is supposed to live, and current drain now is 260 mA 
from the original 220 mils before installing the KAT2. Still higher than 
it looks like it should be, but within spec and radio works well.

It is not necessary to redo the KAT2 adjustments if you have to move R6. 
I did, and they did not change.

Thanks Rich for saving me probably an evening on the bench.

Regards ... Steve WA3SWS