[sdiy] Defluxing/Circuit Trace Repair

[Tim Ressel]

Yo,

Flux can be corrosive over the long term. Absorbs
moisture, I think. Also it can form leakage paths and
cause all sorts of odd problems, especially in
high-impedance circuits. I once fixed about 30 'dog'
boards by cleaning off the 'no-clean' flux with a
brush and buckets of water. These were high-speed uP
boards with lots of critical timing.

Cleaning Method:

Use a 50/50 mix of isopropyl alcohol and TCE. Scrub
with an acid brush with the bristles trimmed down to
about 1/4". then rinse with liberal amounts distilled
water. Drain water. Place boards in a ***warm*** oven
(not over 40-50C) until water bakes out. If you see
any white residue, repeat with CLEAN 50/50 mix.
Remember, as you dip the brush into the solvents,
youare carrying flux back on the brush. I use little
Dixie cups for brushing.\, then toss them.

As for fixing traces, just run small buss wire where
the trace was, then glue down with Loctite Tak Pak or
some other super glue.

--TR

--- Joe Kramer <musetrap at earthlink.net> wrote:
> Hi Folks,
>     What kinds of effects can an un-defluxed board
> cause in a synth?
> The board I have in mind works fine, but it appears
> never to have been
> defluxed, probably as a cost saving measure at the
> factory.  Would I
> gain anything going through the trouble?
>     A second question: Does anyone have advice on
> repairing broken
> circuit traces?  I've seen those trace-fixer pens,
> but at $15 a pop I
> didn't feel like risking it without gathering some
> educated opinions
> first.  Thanks.
> 
> Regards,
> Joe Kramer
> 
> 


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