Good Morning, We are assembling a BGA connector onto a flex circuit. The BGA has leaded balls and the BGA manufacturer uses a no-clean process to attach the balls to the connector and does not clean afterwards. When we assemble the BGA connector to the flex we use water soluble paste and then we clean. After damp heat cycling we have seen some shorts. When we take off the connector we see flux residues on the underside of the connector but not on the flex. So my question is - what are the concerns about mixing no-clean and water soluble? Is the failure likely due to inadequate cleaning or is there something else I should be concerned about. I realize this is probably not the way it should be done but some days you just do what the customer wants - good or bad. Thanks in advance. Steve Kelly Steve Kelly (416) 750-8433 (work) (416) 750-0016 (fax) (416) 577-8433 (cell) --------------------------------------------------- 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 -----------------------------------------------------