Electronics Forum | Wed Aug 17 14:30:58 EDT 2005 | russ
I usually see this with mask that is not fully cured from the PCB shop. This probably agrees with the baking statement that you made.
Electronics Forum | Thu Oct 25 05:58:52 EDT 2007 | reypal
Is there a standard to specify how many times a profile board can be used? if No, then could I say that it depends on the actual board appearance (discoloration,delamination etc.) then it's time to replace a new one. Thanks in advance for sharing.
Electronics Forum | Fri Aug 29 10:18:31 EDT 2008 | rrpowers
We saw this one time when we were trying to develop some lead-free product. It ended up being copper migration. Some of the pads had a brown discoloration and those that did would not wet very well. Your elemental analysis would have shown if ther
Electronics Forum | Sat Sep 13 09:36:53 EDT 2008 | davef
Lemme tell ya, those are weird looking pix. If OSP boards have not been dried properly prior to bagging and sealing, water can leak from via and ruin the OSP, which will turn black.
Electronics Forum | Mon Oct 20 13:17:05 EDT 2008 | jdumont
No pictures pre-paste. I have noticed on a few occasions a couple of boards that look like they have a slight discoloration on some areas of the board. Kind of like a shadow almost on the gold. Josh
Electronics Forum | Tue Feb 10 18:39:06 EST 2009 | solderq
Quick production (no "pasty" phase) > High joint surface quality > Good flux action > No discolored, corrosive, or substantive residue of any kind > Lead-free is not a concern ;o) Any input/ideas are appreciated. Thanks!
Electronics Forum | Sun Aug 16 19:46:48 EDT 2009 | abeasia
Hi Dave F. Thanks for the suggestion, will give it a try. With Appreciation, ABE.Asia
Electronics Forum | Fri Sep 18 07:32:53 EDT 2009 | karthikthebest
I agree with Graham cooper's input. Also note that the brownish color is incremental w.r.t to number of days you hold after the thermal cycle(example: after the reflow)so try to complete all thermal cycles ASAP to lessen the discoloring.
Electronics Forum | Wed Dec 07 15:19:10 EST 2011 | soren
If this is a water soluble flux, then the discoloring is caused by the still active flux microetching the solder fillets. Prevention is to wash off all water soluble flux as soon as possible
Electronics Forum | Fri Jul 20 17:38:06 EDT 2018 | mikedcmt
We have some MLCC capacitors that show some discoloration, or spots. Does anyone know if this will affect reliability? Caps test good - and assemblies function perfectly.
