Electronics Forum | Tue Jul 29 03:32:19 EDT 2014 | cmchoue
The solder in MB become to yellowish after thermal test (100 oC/12HR) I think the problem that is flux residue and I really want to know the principle that why it color change Thanks!!
Electronics Forum | Wed Sep 16 00:03:55 EDT 2009 | linseeg
We encoutered few PCB after IR reflow the PCB pad change color from silver to yellowish / brownish. Our IR reflow peak temp is ~250 degree. The brownish cannot be remove with IPA as well. What is the main reason causing this issue?
Electronics Forum | Sat Nov 21 08:51:35 EST 2009 | patrickbruneel
Sean, Thank you for the feedback. Patrick
Electronics Forum | Fri Nov 20 09:07:43 EST 2009 | Sean
Hi all, Another thing that I would like to discuss here is that I used to come across few reports that mention about the flux residue has great impact on the PCBA impedance, especially when everything become smaller and smaller...I mean, when mother
Electronics Forum | Fri Nov 20 15:45:24 EST 2009 | patrickbruneel
Dave was that a no-clean flux residue? And if so alcohol or VOC free (water based)
Electronics Forum | Sat Nov 21 02:04:47 EST 2009 | Sean
Hi Patrick, Sorry, it should be Intel's Southbridge BGA instead of Intel's Northbridge BGA.. Thanks, Sean
Electronics Forum | Sat Nov 21 08:52:22 EST 2009 | davef
Patrick: The flux was OA, but you can get the same result with low residue flux.
Electronics Forum | Sat Nov 21 16:23:05 EST 2009 | davef
Patrick I can only agree with you about low residue (alcohol based) fluxes, providing you apply the amount specified by the supplier. Amounts in excess of the specified amount can have harmful effects.
Electronics Forum | Wed Nov 25 09:40:56 EST 2009 | Sean
Hi Greg, The board is with immersion silver finishing..One of my friend had the same issue even with PCB OSP finishing.. Besides, no white residue found on the top side... Its only appear on the bottom side but no so obvious... Rgds, Sean
Electronics Forum | Wed Nov 25 10:36:28 EST 2009 | gregoryyork
Is this the Nitric Acid Based Silver finish or the Alkali, I think most are Nitric. Have you tested the solder resist as well for porousity. Cheers Greg