[sdiy] Defluxing/Circuit Trace Repair

[Batz Goodfortune]

Y-ellow Joe 'n' all.

>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?

I'll leave that for someone more knowledgeable on that subject to answer. I 
know that crystals can form and do strange things in certain circuits and 
certain circumstances but I'm not sure this is one of them.

>     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.

I recall a long time ago on a list far away we were talking about those 
things and came to the conclusion that they weren't really worth it. 
Although the purpose we were discussing was a little different. The 
conclusion was that board flexing often breaks the join again but your 
mileage my vary.

Personally I'd tend to use Kynar wire. Yes I know everyone thinks I use 
kynar wire and holt melt for everything but that's not entirely true. Just 
mostly true. I don't floss my teeth with kynar wire. But that's only 
because it's too expensive to waste as dental floss.

Essentially what you do is scrape some solder mask off either side of the 
break so you can tin the track, strip off a little of the coating on the 
wire and then solder it across the break as a bridge. Then it's a simple 
matter of "twizzling" the wire till it breaks off leaving a tiny bridge. 
It's a common enough practice for making board modifications both before 
and after market. In fact it's pretty obvious that Yamaha screwed up with 
the O1V because they had to cut some tracks on the PSU board and rewire it. 
Ironically because they didn't cut the tracks properly the stupid thing use 
to reboot and mess up constantly till I tracked the problem down. It was 
still under warranty but it probably would have taken the clowns three 
weeks. 2 weeks of which would be spent in denial that a Yamaha O1V could 
have actually had a problem in the first place. But I digress.

A guy I knew who was head of the electronics department in the airforce 
here was telling me about training courses they all had to go through on 
repairing multi-layer boards. I don't know what they used to bridge the 
cracks but they use to dig down through the board layers under a microscope 
to the crack, fix the problem then re-build the layers all the way back to 
the surface again. "Don't try this at home."

But if it's just your usual single or double layered board with a broken 
track then kynar wire is probably the easiest thing to use. You can fix 
just about anything with kynar wire. Mir would still be in orbit today if 
they had just used a little kynar wire. I'm going to send a roll to the 
middle east. Should be peace there in no time. It's a little known fact 
that kynar wire is the only thing holding the Australian economy together 
at the moment. Our dollar is only worth 50 US cents at the moment but think 
how much lower it would be were it not supported by kynar wire.

I won't even mention how the whole of humanity could be saved with nothing 
more than a hot melt gun and a few sticks of glue.

Hope this helps.

Be absolutely Icebox.

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