[Elecraft] K2 doesn't work with mic connected

[Don Wilhelm]

Gary,

You seem to be having several problems that cannot logically be related 
to each other.
I suggest that you re-check all your soldering.  Look at it with a 
critical eye.  A good solder joint should have a concave fillet that 
tapers off to an almost invisible edge on both the solder pad and the 
component lead.  If your solder connections have a convex shape to them, 
they have too much solder applied, and that alone can mask a bad solder 
joint.  Unfortunately, the only cure is to wick away most of the solder 
and reflow the remaining (perhaps adding a tiny bit of new flux and solder.
If your solder connections do have that 'rounded' convex appearance, the 
most likely cause is that inadequate heat was applied to the solder pad 
during the soldering process.  Use an iron temperature of 700 degrees F 
or greater (I routinely use 750 degrees).

If when re-flowing the solder you see flux still boiling out of the 
solder joint, that may mean again that not enough heat was used originally.

I cannot emphasize strongly enough - use adequate heat when soldering.  
The solder should flow within 2 to 3 seconds when the solder is applied 
to a spot where the direct heat of the iron tip is *not* placed.  If it 
takes longer than that, your iron is not hot enough.  Few components 
will be damaged by a hot soldering iron applied for a short time (up to 
5 seconds), but they can be damaged by a soldering temperature that is 
too cold because things have to 'heat soak' for a long period to 
properly flow the solder.  Normally 700 deg F. is enough, but some 
boards like the KSB2 and the KPA100 have more extensive ground planes 
and the copper area will wick away the heat more quickly, so a 
temperature of 750 deg F or even 800 deg F is appropriate for these boards.

73,
Don W3FPR

Gary Krause wrote:
> I thought I had a problem with the control board originally.  When I 
> turned on the K2 the "Elecraft" would come up and then go to the 
> frequency.  However, everything was frozen.  Nothing worked and the 
> frequency couldn't be changed.  I re-installed the control board, 
> turned it on and everything worked fine until I plugged in the mic.  
> Then everything froze again.  Unplug the mic and everything comes back 
> to life.   I checked the jumpers for my mic configuration and they are 
> correct.  I'm using a Kenwood MC-60 mic with an internal preamp.  
> However, I don't use the preamp but, I have the jumper installed for 
> it.  Any ideas?
>
> Thanks,
> Gary, N7HTS
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