[Elecraft] KAT2 Null Bridge

2007-11-02 Thread Matt Palmer
I cant get the bridge null to 0V T1 looks right, and all the various
connectors are fine as far as continuity (less than an ohm) any ideas
what to goto next?

Matt
KD8DAO
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[Elecraft] KAT2 Null Bridge Adjustment Problems

2005-08-12 Thread Carl J. Denbow
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.  Anyone have any ideas where I should look for the culprit here?  
Prior to this, the KAT2 checked out just fine in the preliminary tests 
on p. 13 of the manual.  I just need some direction as were to start 
looking for the possible problem.  The only thing that I can think of is 
a possible bad C55.


Thanks and 73,

Carl
N8VZ
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Re: [Elecraft] KAT2 Null Bridge Adjustment Problems

2005-08-12 Thread 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 



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