Electronics Forum | Thu May 05 12:22:01 EDT 2005 | jimmiem
could there have been a solderablity issue with that pad to begin with, allowing the flux in (from improper cleaning of adjacent work) to expadite an error may have happened later down the road?
Electronics Forum | Thu May 05 15:25:38 EDT 2005 | jimmiem
Would a lesser degree of black pad still allow solderability as i seen in my case?
Electronics Forum | Thu May 05 12:00:16 EDT 2005 | russ
Bad cleaning practice is suspect. It is believed that W.S. flux was used to solder adjacent components and then hand cleaned. This is not definite but it is pretty certain.
Electronics Forum | Tue Sep 25 14:08:59 EDT 2001 | davef
Oooo, the solder on the pad and PGA ball is flowing during reflow down the via to the secondary side? Why didn�t you say so?? ;-) Why would you expect that gravity and capillary action wouldn�t force solder to flow down the solder plated via to the
Electronics Forum | Thu May 05 17:15:46 EDT 2005 | russ
You got what I think someone has called a "cold melt". If you were to run your removal profile awhile longer you would not see this. Anyway, you don't have any issues as this is very common (at least in my experience). FYI I was thinking your oxid
Electronics Forum | Fri Nov 23 15:46:06 EST 2007 | mika
Question: We have an issue right know on a prototype batch with via in the pad on an very small pcb 50x50mm (in a panel of course). The designer has no room to move the vias as they said. The pcb is to packed with components also 8-layers. It is also
Electronics Forum | Thu May 05 09:17:58 EDT 2005 | jimmiem
I tried soldering to several of the black pads and was successful, the solder stuck with no hesitation. so i guess this is not truly "black pad"? would that be a correct statement? What causes this blackening that looks like oxidation under the mic
Electronics Forum | Thu May 05 12:31:27 EDT 2005 | russ
Not in this case, these BGAs were lead free and the profile used was for a lead part. I guess I will give you the whole story. These boards were sent to us from a customer to have the BGAs replaced for an unknown to us reason. We removed the parts
Electronics Forum | Wed Jul 14 16:59:52 EDT 2010 | swag
Solder paste on the pads will keep part aligned. If you do not use paste, you will need to apply tacky flux. You should not run without one or the other.
Electronics Forum | Thu Jun 19 21:39:31 EDT 2008 | mika
Hi, we used to have a RoHS package with uBGA 380 Solder ball's 0.8 mm pitch approx 15x15 mm, bump size is 0.4mm on a 0.33mm pad. Suddenly we need to use another vendor for various reasons. However, the new bump size is 0.45mm according to specs and t
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