[Elecraft] Issue with mounting KX3 RF board Rev D

[Phil Wheeler]

Marcus,

I had the same experience with a stripped 
standoff. It was late on a Friday afternoon as 
luck would have it. I called Elecraft and had a 
replacement standoff the following Wed. I'm in the 
Los Angeles area, reasonably close to Elecraft, 
and with quite a few hardware stores nearby. I had 
no luck finding a replacement locally. In your 
case the wait for a replacement standoff is likely 
to be longer than mine -- and that five days was 
pretty frustrating, with the KX3 spread out in my 
operating position.

I suggested at the time that a spare standoff or 
two be included in the kit -- because it is not a 
piece of hardware anyone is likely to find in a 
local hardware store, and it is pretty easy to 
strip, as you and have demonstrated. I guess my 
recommendation fell on deaf ears :-)

Unfortunately the only way I could comment on your 
measurements and following discussion would be to 
disassemble my KX3 and do some measurements -- and 
that would risk stripping another standoff with no 
spare on hand. Perhaps someone from Elecraft can 
comment.

73, Phil W7OX

On 12/6/14 9:39 AM, Marcus Busch [DL1EKC] wrote:
> Hi everybody,
>
> I'm just putting together my KX3 kit. While mounting the RF board Rev D to the
> bottom cover I zipped off one of the M-F standoffs using rather little force.
> As I usually have a good feeling which force may be used on these standoffs I
> started investigating things a bit.
>
> After removing the RF board I callipered the remaining gap after fully
> screwing in the M-F standoff into the round standoff at the bottom cover. The
> gap is 1.9 mm / 0.075 in. The RF board PCB has a thickness of 1.7 mm / 0.066
> in. The lock washer was in place when measuring the gap (see photo). The pan
> head screw at the bottom cover has a length of 4.8 mm / 0.0177 in which
> matches the numbers in the instruction manual.
>
> Obviously it is not possible to securely mount the PCB to the bottom cover
> with the above dimensions. In my understanding those screw points are being
> used as grounding points so there should be a reliable electrical connection
> as well.
>
> Did anybody here also experience this issue? How did You solve this?
>
> I could use two split lock washers between PCB an M-F standoff, but this would
> change the distance between RF board and KXAT3 board and front panel.
>
> Or do I just have bad luck with tolerances?
>
> Any idea or hints are highly appreciated.
>
> VY 73
>
> Marcus, DL1EKC