[ppl]

The standard Practice in manufacturing is to First Scrub the Etched and drilled Board after the Conformal Coating is applyed with a scotch-bright Pad and very warm water. This makes sure the solder has a good surface to stick to. Then after soldering wash the Board. aos it is not the Conformal coating that is the Problem it is the leftover Flux> this stuff is corrosive and conductive and since it is organic Rubbing alc. will only smeer it all over the board not remove it. This type of Flux removal is way unexceptible in Manufacturing and as sutch should Be for any DIY project you take pride in.

 

[eric343]

So how would you reccommend removing the flux? I think leftover flux may be causing a short on my CHA47.

 

[aos]

Hm... ppl, where is the flux coming from? When I etch the board, believe me, it's pure copper except that film over parts not meant to be etched.

I though conformal coating is for example a spray (that I have), with about 10 huge warnings (poisson/flamable/carcinogenic etc.) that forms a hard epoxy after drying and is very hard to remove. And is usually sprayed over both the board and the components once they are soldered to protect it from the elements etc.

 

[eric343]

Usually flux comes from the solder (if it's flux core solder) or you manually apply it to the board (for non-fluxcore solder).

So my method of using isopropyl alcohol+toothbrush won't work then?

 

[ppl]

Eric: If the Dishwasher method is unavailable then you need a solvent to desolve roson. Acitone will but may damage the Fiberglass board. Grain Alc (Everclear) will also work. The Toothbrush Probaly left remnents of flux that you had to scrape away. I do not think this is the Problem with your amp since a now product unless it is High voltage or frequency most of the time works with Globs of Flux still on board. and only in time after heat and other factors cause a malfuntion. and this surly is true with the OPamp you are using. However the flux will cause Problems down the road evean with the Circuit yoy are building. i would suspect in your amp that a wiring errer or oscilation is the case.