Jim The circuit actually is from ERG incorporated into our customer's design. The failure is usually the transformer burning up (over heating) or if a winding goes open the input transistors blow (smoke fire ect.). Our Test Eng. is thinking there may be some small leakage across the cap (or PCB). The backlight is 6mA typical and the driver is also 6mA, so his thinking that any increase in the load current and the transformer fails. Then the question was raised about n0-clean potentially contributing to this. We have only seen a couple boards that had any sign of possible arching at the cap. The cap is an 18pf 4000v 5% COG from NovaCap. I did manage to get a hold of a PCB layout recommendation for the circuit which suggests a slot between the cap pads and to conformal coat. (The customer did not do this) _____________________________ Andre Leclair Process Engineer Ansen Corporation 315-393-3325 ext 293 315-393-7638 FAX -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: Wednesday, April 05, 2006 2:28 PM To: [log in to unmask]; [log in to unmask] Cc: [log in to unmask] Subject: Re: [TN] Arching or Current Leakage Andre, What is the failure mode of the circuitry - leaky capacitors on the output of the backlight driver? What type and voltage rating are the capacitors? Are there any external signs of the failure mode, ie burn marks, electro-migration paths, etc? Jim Carlson Sr Quality Assurance/Reliability Engineer Rockwell Collins EW-SIGINT Phone 443-489-9121 Fax 443-489-9290 Andre Leclair <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 04/05/2006 02:11 PM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to Andre Leclair <[log in to unmask]> To [log in to unmask] cc Subject [TN] Arching or Current Leakage We have a customer that has a portion of a circuit which randomly fails. The circuit is a backlight driver (500volt 6mA). The output caps are 0.100 spacing of the terminals. The process used is No-clean. Can the No-clean contribute to failures of the circuit (ie promote arching or current leakage across the body of the output caps). ??? --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 1.8e 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 -----------------------------------------------------