[Elecraft] KAT2 bridge null adj.

[Don Wilhelm]

Allan,

Do you actually have power flowing through the KAT2?  Power is necessary 
to generate voltage at the diodes D1 and D2 cathodes.
If you can temporarily connect an external wattmeter between the KAT2 
and the dummy load, see if power is getting through.
Once you determine that there is power flowing out of the KAT2, remove 
the external wattmeter before attempting to set C55 to its final setting.

If you do have power flowing and still have a display of 000, be certain 
you have the potentiometers set to full clockwise (max rotation).  Check 
the orientation of D1 and D2 and look for soldering problems.
Measure the DC voltage at the wiper of R2 - If you have voltage at the 
wiper of R2, but still a zero display there is a problem between R2 and 
pin 4 of U1.

73,
Don W3FPR

Allan Glasdam wrote:
> Hi guys
> After receiving great help from Don off list with the KAT2, I have a new 
> "problem"
> KAT2 assembly and operating instruction page 16, second from bottom 
> says: adjust C55.  Hold in TUNE button and release when...
> Adjust C55 as close as possible to 000.
>
> When I press TUNE the display flashes ATu and then reads 000 constantly 
> until I tap menu. It´s not possible to get any movement when turning C55.
> T1 on KAT2 is rewound, soldered and checked.
> Any suggestions? I would be glad for a hint, where to search.
> 73
> Allan OZ8A
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