Thursday, April 11, 2013

K2 Alignment Testing Begins

The build with the K2 continues on and I am now at the second alignment testing stage. With the front and control boards completed I’ve reached halfway through the RF board with most of the components for the receiver now fitted.
The alignment testing consists of a number of actions to prove all is working correctly, these are the 4MHz ref oscillator, RF alignment, AGC threshold and IF filter alignment.
Sadly though I’m stuck on the oscillator test and am unable to get signals within the approved spec.  Searching the K2 forums this is a well-known problem and normally means some soldering/bridging issues or a component problem or perhaps a component misplacement.
So at the moment I’m running checks within the oscillator circuit searching for what may be at fault. One thing I did suspect was the toroid’s which have the correct windings (I've double checked), but don't seem to have a decent amount of tinning on them and I suspect I will have to remove and re-tin. I've never had the issue of toroid winding, in fact I find it quite therapeutic although hand winding five of them in one afternoon does tend to cut your fingers up!

I think with a bit of time and patience I’ll get there, normally with problems like this it’s some minor issue that the builder has missed and when the problem is found you can never believe that such a small error could cause the issue.
The good news is that the forum provides plenty of support and talks you through each check in detail so you are bound to find the cause in the end. Also by chance a fellow ham just down the road is building a K2 so if needs be we can get together to discuss. 

Hopefully in the next post I'll have moved on and perhaps start to see light at the end of the tunnel!

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