[Elecraft] K3 (not S) Antenna tuner strangeness

[Don Wilhelm]

John,

Yes, the "earthing" connection to the SO-239 jacks is important.
That connection is provided by the mechanical connection to the standoff 
between the right side panel and the KAT3.
The assembly manual instructions will provide adequate connection - 
first insert the side panel screw through the 2-D connector and then 
tighten the standoff to the 2D connector, and lastly, put the screw and 
lockwasher into the standoff.

The problem is that *if* that long screw in the upper rear corner of the 
right side panel is removed for any reason, it cannot be tightened 
properly without going through the entire procedure - tighten the 2D 
connector, then tighten the standoff and finally tighten the screw into 
the standoff.

If one tries to remove that screw from the right side panel, it is 
impossible to re-tighten everything without going through the entire 
process in order.  The threads of the 2D connector cannot be properly 
tightened to the threads of the standoff.

A shortcut is to drill out the screw threads on that 2D connector 
allowing the screw to pass through the 2D connector without threads.  
That will permit the screw threads to pass through the 2D connector and 
be tightened onto the standoff.

I recommend that anyone removing the right side panel from their K3/K3S 
to drill out the threads in this hole of the 2D connector so it can be 
assembled tightly without going through the entire procedure of first 
tightening the 2D connector, then the standoff and finally the screw and 
lockwasher.

73,
Don W3FPR

On 7/23/2016 9:09 PM, g3pqa at onetel.com wrote:
> Guys,
> I've run into something on 80M trying to use the internal antenna tuner.
> It fails to tune to a low SWR. Brian K3KOI had a similar problem but never quite got to the bottom of it because partly intermittent, possibly multiple faults.
> In the end to fix it:-
> a) I rewound one of the swr sensor toroids (centre wire had possibly arced to ferrite because I disconnected antenna by mistake and tuned), and
> b) fixed a new earthing wire between KAT3 chassis and SO259 Ant1 socket body. (possible poor earth connection via KAT3 securing pillar to side panel)
> John G3PQA
>