[Elecraft] K2 VFO encoder / control board close fit

[Mark Petrovic]

While performing the initial power on tests on my K2 S/N 7809, I noticed
that the VFO knob/display tuning test produced a sluggish, intermittent, or
no change in display when I turned the knob in either direction.

I proceeded to remove the two chassis screws securing the control board to
the front panel board.  This allowed the control board to relax and
slightly fall away from the front panel board, toward the back of the
radio, opening up the space between the front panel encoder board and the
control board. The display was at once responsive to knob turning on all
RATE settings.

Next, I slipped a piece of paper between the encoder board and the control
board, then reattached the control board to the front panel board with the
chassis screws.  The display continued to be properly responsive to knob
movement.  When I tugged on the paper to see how tight the fit was, it
resisted being slipped from its position.  It was fairly pinned down.

Here is a photo of the control board backside taken at a glancing angle,
showing the joints for J1 in the foreground, and the pins of the U6 socket
behind that.  The socket pins should probably be trimmed, which I did not
anticipate.  The other joints, while not necessarily overly beautiful, I'll
also check for height.  It's not clear to me which pins on the encoder
board are shorting to which pins on the control board, but it seems clear
that some are.

https://photos.app.goo.gl/KDzlAixNghg2tmhy1

If after trimming the U6 socket pins the problem persists, I'll leave the
paper slip in, but I don't feel great about it.  The paper could fail on
these sharp solder joints given vibration over long periods of time.

Has anyone else had an experience like this where the front panel board
meets the control board?  I believe the manual talks warns about this
condition.

Thank you.

Mark
AE6RT


-- 
Mark