[sdiy] Defluxing/Circuit Trace Repair

[Joe Kramer]

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