[Elecraft] K2 Changes modes when pushing A/B

[Don Wilhelm]

John,

That sounds like there is some sort of path between the BANK1 and BANK2 
signal lines on the front panel board.
Did you attempt to clean the board of solder flux?  If so, you may have 
left some residue on the board (likely under the switches) that now must 
be completely cleaned, even if that means removing the switches.
The combination of flux and solvents can create conductive paths that 
are very difficult to track down.  Do not remove the flux, it is not 
conductive (just looks messy).  If you must clean off a really messy 
looking area, do it with a bit of alcohol applied sparingly with a Q-tip 
or other small swab and work in a small area at a time.  Make sure you 
get it all off in that area, as I indicated, leftover flux plus solvent 
can be conductive.

If you did not attempt to clean the board, then look very carefully at 
the soldering of U3.  Reflow the solder adding a bit of solder (actually 
you will be adding a bit of flux).

73,
Don W3FPR

On 7/30/2011 8:00 AM, John Oglesby wrote:
> My recently built K2 - no options - exhibits an odd behavior.  When I
> push the A/B button it occasionally pauses for a moment like it is
> thinking - and changes modes instead.  This happens in every combination
> I have tried, working split, or just changing from VFO A to B or B to A
> or using REV.  I have carefully tested this and I am positive that the
> mode switch is not being touched, nothing appears to be flexing, and
> there doesn't seem to be any other odd behavior.
>
> I tried to look back in the reflector, but I can't seem to find a search
> function in the archives - so is this a known issue, or have I found
> some hidden feature?
>
> Thanks&  73
>
> John
> N9RE
>
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