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Date: | Fri, 25 Jul 2008 09:58:43 -0400 |
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Hello Technetters,
We experienced some problems after reworking circuit boards, I would like to have inputs on the following.
The problem found is capacitor leakage. The capacitor was added manually after automated production. The boards were coated with acrylic conformal coating.
1- How should a WS flux be cleaned after a rework?
2- Can WS be cleaned with alcohol? If not what would happen?
3- When reworking a SMT component, can WS flux be trapped under the component and cause leakage. The rework was cleaned with a brush or similar method.
We think that the rework method was as follow (to fix a possible contamination under the component)
a- SMT component is removed (possibly directly through the conformal coating)
b- Using coating thinner, the area is cleaned and verified under UV to ensure no coating is present.
c- WS flux is added
d- Component is soldered back in place
e- Area is cleaned with isopropyl alcohol
f- Coating is added
I think I've read that cleaning WS flux with alcohol is a NO NO! Can anyone confirm and comment?
Jean-Francois
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