[Elecraft] 1/4" paddle jack rear panel of K3

[Don Wilhelm]

Bob,

I can't judge just how much force you are applying nor how loose your 
jack really is.
Yes, there are no external nuts on those jacks, and none are needed.  
The jack is fully supported by the board, and the holes in the rear 
panel are oversize to allow easier assembly and allow for mounting 
tolerances of the jacks to the RF Board.

Two things determine how stiff those two 1/4 inch jacks *feel* - first 
is that some will have the flange of the jack body actually tight 
against the inside panel surface - in that case it will feel tight 
because of the friction with the panel.
Secondly, the key jack will have more vertical movement than the paddle 
jack right next to it.  If you examine the assembly manual photos 
carefully, you will see that there is a support screw (and standoff) 
just to the right of the paddle jack, so that will limit the vertical 
movement of the paddle jack much more than the key jack (which is 
further away from any support) - when you attempt to move the key jack, 
you are actually flexing the RF Board.

So bottom line - don't be concerned about it.  If you want to put nuts 
on the jacks, you may do that, but I would not recommend that - If you 
tighten the nuts enough to pull the jack flange up to the rear panel, 
you may actually damage the jack or pull it away from its solder pads 
(and that can damage the solder pads)
The RF Board will stand the amount of flexing that is normal with 
inserting and removing the plugs - it is not designed to withstand a lot 
of flexing from "repeated demonstrations" to figure out just how much it 
flexes.

Some things are designed to allow for a bit of movement - trying to 
defeat that movement allowance can cause damage - that is true of many 
mechanical assemblies including the enclosure design of the K3.

73,
Don W3FPR

On 1/31/2012 1:56 PM, Linda and Bob wrote:
> Rick,
> I just checked the rear panel at the paddle jack area. There is no external lock washer or nut on this outside threaded jack. It may be possible to place a round or hexagonal nut on the outside of the jack on the rear panel. This may help to tighten the jack from the outside of the radio cabinet . I believe that there isn't an internal nut holding this jack. It must be soldered to one of the internal PCB's.
>
> If I knew the tread diameter of the paddle jack, I might be able to install a round nut over the threaded shaft of the paddle jack (on the outside). Maybe Elecraft could send me this part. The 1/4" key jack next to the paddle jack is tight with no wiggle. It must also be located on the same PCB.
>
> I have to check the assembly manual for this illustration. I only have the operating manual. My K3 was factory built. The paddle jack has been loose since I purchased my K3/100.
>
> Perhaps, Don, W3FPR knows what to do? I will also contact Elecraft service as well as Eric.
>
> Only the rear portion of the bottom cover needs to be removed (figure 2; page 8 of the K3 manual). It looks like there are 7 screrws which are 3/16" long with no lock washers as well as 3 screws with tooth lock wahsers 1/4" long [10 screws in total]?
>
> Bob Wilderman, K3SRO
> dlrwild1 at verizon.net
>
>