[Elecraft] Organic Rosin Core Solder

[John Bonk]

Ron,

I'll try to find the page I reference, but it definitely said water-soluble.
I can see the residue on the board, and the DMM shows a path across the
"gunk".  The corrosion seems to be returning also; only 16 hours after the
last brushing.

John

-----Original Message-----
From: Ron D'Eau Claire [mailto:rondec at easystreet.com] 
Sent: Saturday, May 14, 2005 2:05 PM
To: 'John Bonk'; Elecraft at mailman.qth.net
Subject: RE: [Elecraft] Organic Rosin Core Solder

Wow Joe!!!

Rosin is extracted from tree sap - Pine trees mostly. It's "organic" and
water soluble by definition. The "water soluble" doesn't refer to the
solder, only the rosin. 

Something else happened to your K2 besides using an "organic" core solder. 

Maybe accidentally using an acid flux instead of rosin would do that.
Perhaps a mis-marked roll of solder? 

I've never gotten acid flux anywhere near a PC board, or any other
electronics for that matter, but my impression was that the damage it does
takes months, at least. 

Ron AC7AC

-----Original Message-----
Just a friendly warning to those who may not know the exact origin of their
solder.  I used a Kester solder that was labeled "organic rosin core" on my
K2 (only 75% of the RF board) while I was waiting for a re-supply order to
come in.

Fast forward one week:

Minus one sloppy joint, my K2 fired up and was putting out the expected
power during part three of alignment.  Big whoop of satisfaction follows.
Completed kit build with no issues.yet.

Fast forward two weeks:

Turned on the K2 to do some listening, upon hitting the tune button, I see
the High Current warning.  After pulling apart the K2 again, I notice that
75% of the solder joints on the RF board seem to be suffering from some sort
of corrosion.  Attempted to clean small portion with alcohol, very little
luck..showing strange resistance values across the board.

Three hours later:

After two and a half hours of pulling my hair out, I decided to do another
check of the solder to make SURE that I didn't make a mistake.  A bit of
digging turned up the ORGANIC=WATER SOLUBLE.  The values I'm seeing and the
corrosion of the RF board support this finding.

The first attempt was a q-tip and water.  Second attempt was distilled water
and a toothbrush to help the process.  Neither has proved helpful and I'm
still showing strange resistance values from the collector to ground on Q6,
7 and 8, high current warning on keying.  Voltage checks show within specs
for RF board during receive.

So now I sit with a defunct K2, any suggestions for what I can try before I
order K2-Part Deux would be appreciated.

Lessons learned:  Throw away all unknown solder before you start.  Don't use
organic core solder.  

John

KD7ZYR