[Elecraft] KAT2 problem: bridge null adjustment

[Bob - AG5Q]

Hi Stephan,

Try checking for continuity between the Center Conductor of the ANT 1 jack
and ground. There should be a DC path to ground through the TX output
transformer, T4, even when the power is turned off.

With only 0.1W, the voltages at U1 pins 4 and 5 on the KAT2 board should be
less than 1V but greater than zero.

73/ Bob - AG5Q
=========================================

----- Original Message -----
From: "Stephan Walder, HB9DDO - K2" <k2@hb9ddo.org>
To: "'Elecraft'" <elecraft@mailman.qth.net>
Sent: Tuesday, January 21, 2003 3:10 PM
Subject: [Elecraft] KAT2 problem: bridge null adjustment


> Hello K2-owners
>
> I'm on the way to assemble/install the KAT2 option. Everything looks good
> including the preliminary tests. When I came to the point where I'm
supposed
> to adjust C55 for the bridge null I ran into problems. Even with power
> reduced to the minimum at 0.1W I get a high current warning when I tune. I
> checked several times to make sure that the dummy-load/rf-power-meter is
> conncted to the right Ant jack (1) and the correct antenna is selected. My
> K2 reacts as if there were no antenna at all. I even checked the cable
> between TX and dummy-load, went back totest without KAT2 to make sure
> there's no problem there.
>
> According to the troubleshooting section I checked on T1, even re-soldered
> it to make sure there's no problem there...
>
> Fellow hams, I'm stuck ! Any help/idea/suggestion is welcome. Anybody seen
> this or a similar behaviour before ?
>
> vy 73, Stephan, HB9DDO, K2 S/N 3128