[Elecraft] KAT2 Null Bridge Adjustment Problems

[k4zm]

I've built the KAT2 and have become "stuck" at the Bull Bridge
Adjustment stage (P. 16 Rev. D Manual).  No matter where I place the
trim capacitor C55, I get "Hi" on the screen when I do a Tune in CALn
mode.



Carl:

I usually make this adjustment using an old analog voltmeter on the lowest 
dc votage scale.  You can see the null much easier.  I connect the meter 
negative lead to ground and the postive meter lead to pin 4 of U1.  Then 
follow the directions in the manual.  If it will not null then you probably 
have a problem with T1.  I would guess that 95% of the problems with a null 
function are caused by T1 problems. (poorly tinned transformer leads, the 
omission of the link between pins 5 & 6 of T1 and the leads of T1 not 
installed in the correct holes in the board)

73

Jim Younce K4ZM
K2  SN: 18