1. with a good water wash, just th same as when you solder the beastie with a WS flux. No messing, no short cuts. 2. categorically NO! Alcohol may not dissolve the residues, either organic or metallic 3. Yes! This is why you need to give it a full-scale wash. You cannot clean with a brush: all you will do is harm by spreading those ionics all over the place. WS=WATER soluble - un point, c'est tout! Brian Jean-François Bissonnette wrote: > 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 > > > > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 > ----------------------------------------------------- > --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------