In a message dated 5/29/99 5:26:06 AM Central Daylight Time, [log in to unmask] writes: Hello Brian Could you tell us the type of cored solder that was used and was any VOC free low solids flux used to help soldering. I have seen were unreacted flux of this type attached the solder joint and opened the circuit. (these fluxes are very good at soldering and leaving a benign residue (no clean) if properly activated per the mfg's thermal requirements). The second question that comes to mind would be is there any cleaning solution used on this wire solder joint and if so what was the method of cleaning. Because if water soluble flux is used and cleaned with water or one of the bench top cleaners then the residues that were left behind would be capable of this corrosive attack. Interesting Opportunity to learn Terry Munson CSL Inc. 765-457-8095 << Hi Netters I've had an incident where two fine wires twisted and soldered together in a transformer assembly have gone open circuit. When the assembly is stripped down the twisted wires appear to have a residual solder coverage but insufficient to provide a proper solder joint. there is also a light powdery residue all over. It's as if the wires were soldered OK originally and some chemical reaction has stripped the majority of the solder away and left a corrosion product. The joint is within a sealed assembly, is covered locally in a protective tape and the transformer is impregnated before wiring. Does anyone have any history or knowledge of any reaction between transformer varnish and solder? I appear to remember some problems with phenolic fumes attacking metals however I've never seen solder attacked in this way. Perhaps David Copperfield's been in town !! Any feedback appreciated. Bryan Kerr Alenia Marconi Scotland >> ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################