Dear sir, Mostly I belive your problem is the water contamination and possible cause is improper cleaning process. Nevertheless, please ensure your income PCB quality because the brown/orenge can be caused from the gold finished process of the PCB maker and it look like discoloration on the pad and this defect can erased by rubber also. Following are the guideline to verify your process. 1. Please kindly clean that contamination with the IPA(Alchohol), if the contamination is water contamination then it can be cleaned else can not. 2. If Your flux is water soluble flux and your cleaning system has the pre-wash, please kindly check the pre-wash water has been drained out do not circulate to the wash tank. The pre-wash is the wash to clean the gross contamination then the water from this section has a high dirty. 3. Your cleaning system is the circulating water system, please be reminded the water degradation will happen after half to one hour cleaning depend on your throughput and your component density on the board and your flux type. Therefore, after an hour cleaning the wash water will unclean. Please kindly check your process and specify the water change schedule to serve your cleanliness requirement. 4. Check the drying zone. Drying zone has two sections, hot air blower (50-60 degree C) to blow the water off the board and dryer to bake the board dry. Normally, if the blower is not completely work then the board will has some water drop and this water drop will be dried at the dryer section. What is happen??, The board pass the dirty water, remain the water drop and water vaporize the final is deposit of all cleanliness on the board. Hopely you can solve your problem. With best regards, Noppadol S. At 10:20 3/7/98 -0500, you wrote: >I am experiencing a problem with my Au/Ni/Cu circuit boards. During the >cleaning process in warm (120f) DI water some of them are exhibiting a >"contamination". In certain areas (random) I am getting a discoloration >on the pads. These are non-soldered connections of the board. Other areas >on the board are soldered (hand) and have excellent >solderability/wettability/solder coverage are generally bright, smooth >and shiny. Sometimes this does not occur until the assembly has been >washed 3 or 4 times throughout the production process. The discoloration >appears brown, orange (like rust) and even dark blue to black. It also >appears to be removed with an eraser. Does anyone know what is going on >that would cause this condition to occur? I am concerned about the >condition with respect to contact resistance (keypad/dome application). >Will it get worse even if I can rub it off? > >My circuit board supplier is on plant shut-down today. Any input on this >matter would be greatly appreciated! Technet or otherwise. > >Douglas A. Hooper, Sr. >Process Engineer >Luminescent Systems, Inc. >[log in to unmask] >(716)655-0800 x163 >(716)655-0309 fax > >################################################################ >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 < >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 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 ################################################################