Steve,
You should be able to balance the wattmeter bridge even if the ADC
inputs to U1 are damaged open - if they are damaged in a shorted
condition, yes they would interfere with the balance adjustment.
I suggest that you try rotating the pots to the full CCW position and
then attempt to balance the bridge while measuring the DC voltage at the
hot end of R2 - try to adjust for a minimum reading on your DMM rather
than a minimum on the K2 display. If that is not successful, then look
at C54, C55, R3, R4 and T1 carefully. But if that null adjustment is
possible, you likely do have a problem with U1.
We had some nasty thunder-boomers over here in the Wake Forest area
yesterday and we disconnected everything - I think Chapel Hill got hit
harder - so if you had antennas connected ---!
73,
Don W3FPR
Steve Jackson wrote:
> K2 #771, the world's most experienced Elecraft, popped D1 and D2 on the
> KAT2. I fear that it also took out the two ADC inputs on U1. CALn does not
> work after replacing the diodes. The reading is very noisy. There is also
> not any power control which could mean something else is also fried. Anyone
> else ever have this happen and if so what did you do to fix it?
>
> Steve KZ1X/4
> Sent via Motorola Droid
> >From W4EZ field day site
>
>
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