[Elecraft] KSYN3A mod problem

[Don Wilhelm]

Fred,

Gary and I both have been using acetone for a long time.
If the board is flooded, the results can be catastrophic since residue 
flows under components and makes a mess.
But carefully applied with a swab or small brush to a small area and 
mopped up with a paper towel it will do the job very well.  The contact 
time *must* be short, and that is why one must work in small areas.

Yes, alcohol can do a good job of cleaning flux too, but needs to have 
the same precautions - it can make just as much of a mess or more 
because alcohol attracts water vapor and causes it to condense on the 
surface being worked.  Dip an opaque object in alcohol and remove it 
with a paper towel - note that the object will be wet with moisture.

Besides, the job for the particular problem stated was not flux removal, 
but removal of some unknown compound from connector pins. Alcohol is 
likely to be ineffective.

73,
Don W3FPR

On 9/7/2015 7:02 PM, Fred Townsend wrote:
> Don:
> Acetone should NEVER be used in electronic assembles. Acetone causes both
> long and short term effects on various components including the PCB. It
> effects epoxy, lacquers, paints, and plastics, particularly polystyrenes
> where its effects are almost instantaneous.  Pour some in a polystyrene cup
> and watch it immediately cloud up.
>
> >From Wikipedia:
> Acetone is a good solvent for many plastics and some synthetic fibers. It is
> used for thinning polyester resin, cleaning tools used with it, and
> dissolving two-part epoxies and superglue before they harden. It is used as
> one of the volatile components of some paints and varnishes.
>
> Polyester resin, also called gel coat, in case you don't know, is the stuff
> PC boards are made of. Leave acetone in the paint department where it
> belongs. I suggest alcohol, any kind as long as it pure, be used for
> de-fluxing PC boards.
>
> 73, Fred, AE6QL
> -----Original Message-----
> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Don
> Wilhelm
> Sent: Monday, September 7, 2015 2:43 PM
> To: Nick Lelyak
> Cc: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] KSYN3A mod problem
>
> Nick,
>
> Yes, but it fails when it cools again - something is not making good
> contact, and it may be residue from the cleaner.  I can't be certain of
> that, but I would get that cleaner residue off and try again.
>
> I would suggest that you remove the cleaner residue from the contacts with
> acetone - apply it with a brush or cotton swab and immediately wipe the area
> with a clean cloth of paper towel.  Do only a few pins at a time, and do not
> let the acetone dry on the contacts or board.
> You may want to mate and unmate the front panel and RF board several times,
> cleaning between each to hopefully clean some of the 'goop' out of the
> female header.
>
> If you do not have gold pins on the connector to the front panel, consider
> asking Elecraft for the gold replacement pins.
>
> 73,
> Don W3FPR
>
> On 9/7/2015 5:27 PM, Nick Lelyak wrote:
>> Thanks Don, Guy
>> appreciate yours quick response.
>> I found out that problem disappears when front panel warms up to 37 C
>> and more.
>> Looks like problem somewhere in FP. To clean main connector I used
>> Electronic Contact Cleaner. It may works not so good as Deoxit which
>> is not widely available in Canada. In any case to move on have to buy
>> Deoxit first.
>> Thanks again
>>
>> 73, Nick VE3FJ
>>
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