[Elecraft] K2 - Board Cleaning and Conformal Coating

[Don Wilhelm]

  John,

Cleaning the K2 (K1, KX1 too) boards is not recommended.  The flux is 
not corrosive in its native state, but in repairing many Elecraft 
transceivers, I have seen cases where attempts at cleaning the boards 
resulted in failures due to leakage paths created - after being 
subjected to cleaning compounds, enough residue remains to cause 
problems.  Any fluid running under connectors or under ICs, relays, or 
other components can (and has) caused problems.

Yes, the switches should be avoided, the toroids may be another 
candidate depending on the cleaning method.  The LCD and the bargraph on 
the front panel are examples that come to my mind.

However, you sound like you have professional cleaning tools at your 
disposal, so clean the boards at your own risk.

I have repaired several transceivers that were used in a beach 
environment, and not one of those repairs could I attribute to the 
environment - the exterior may have taken a beating from the salt air, 
corroding the BNC connector shells, the outside of the key jack, but the 
boards inside the enclosure remained free of any apparent corrosion.  
 From the evidence I have seen conformal coating is unnecessary.  I do 
not know if it would do any harm.  It may make future component removal 
difficult.

73,
Don W3FPR

On 6/1/2011 3:05 PM, John Huggins, kx4o wrote:
> All,
>
> Being in the electronics biz, we usually wash boards post assembly with
> the usual products and in accordance with IPC610, etc.  Often, the boards
> are sprayed with conformal coating: Some to handle "condensing
> environments" and others just because someone wanted it.  My operating
> locations will include salty beaches and moist mountains.
>
> I couldn't find details in the K2 manual concerning these steps.  I did
> find a few posts in old Elecraft archives, but need to ask...
>
> Are there any components used in the K2 boards that will not tolerate
> typical board washing procedures? (Most modern components expect this
> step, but some don't - often switches)
>
> Is there any reason not to conformal coat the boards once complete? (Cost
> is no object to make this last a long time in beach environments)
>
>