[Elecraft] K2 - Resonate noise on audio

[Phil Wheeler]

It sounds like a bear, Jason. But I know you'll 
find it eventually, especially with input from Don 
W. and Co.

I still think the SSB board is the likely culprit. 
But did you do any other mods at that time, like 
the A to B mod set? Good to look in those areas 
too, if you did. I've done *most* of those 
updates, but generally not the post-2002 KPA100 
mods and updates: I've had zero issues with mine, 
perhaps because the KAT100 gives it a happy 
environment.  The one recent mod I really 
appreciated was the AF gain pot mod. No 
components, but traces to cut and jumpers to add 
on the three main boards -- a major disassembly.  
But well worth doing (likely done on yours, since 
I think the mod has been around since 2001); easy 
to check for by looking for the long jumper on the 
RF board at the front on the underside.

K2 is a great rig. I did a receive compare with my 
K3 this morning and it's still one of the best 
there is. It is nice, with the new rigs, to not 
have the need for disassembly for firmware 
updates. Of course, not likely any more for the 
K2!  Mine was ten years behind in Feb so I did all 
the needed F/W updates then.

73, Phil w7ox

On 3/19/14, 11:12 AM, Jason V wrote:
> Thanks Phil.
>
> My wife is IPC-7711/7721 and had her inspect my work when it was complete,
> so pretty confident there.  That and I rechecked it several times since the
> problem began. Removed the old crystals, cleaned up the vias with
> solderwick, re-installed using insulator pads, and soldered the ground tab
> to the side of the crystal approce 1/8" above the base.  All the cans
> measured for continuity to the ground plane.  Have a metcal soldering
> station and it makes working in dense layouts easier, not to mention temp
> controls.  No one is perfect though so I could pull the KSB2 and put a few
> jumpers in it's place.  The problem will either follow it or stay.
>   
> No.  Wish I had stopped to check the K2 mods first.  Usually I take an
> incremental approach to this kind of thing but since I had the radio all
> apart I did them while I was in there.  So I don't know exactly when the
> problem was introduced.
>    
>     
>