Electronics Forum | Wed Apr 13 21:17:18 EDT 2022 | stephendo
If it was ROHS, I would say that the pads are definitely dissolved away. And it sounds like that is the case here. Your best bet is if it is class 2 and the barrels are at least 50% then push for them to be accepted. If you are trying for more barr
Electronics Forum | Thu Aug 13 14:10:01 EDT 2015 | markhoch
Hi Sam, I have a feeling that what you're trying to communicate is that your DPAK's are skewing off the pad during reflow. This is caused by a thermal "mismatch" where the solder paste on one side of the DPAK becomes molten before the other, then th
Electronics Forum | Thu Oct 30 22:29:58 EDT 2008 | davef
For most applications, a nice square [or rectangle] pad works just fine. Assemblers ship boat loads of boards with these every day. It's reasonable for tight decoupling capacitor requirement applications to use round or radiused pads for components
Electronics Forum | Thu May 05 11:50:03 EDT 2005 | russ
Just went through this with a customer. Removed BGAs and noticed discolered pads at some locations. It was determined that these were open connections that had some type of flux migration between the ball. They also took solder readily. This may
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 | Sun Apr 11 11:39:52 EDT 2010 | manchella
When we have sent some of motherboards for reliability testing in a tird party laoratory. It is found that when Dye&Pry is done after 600 cycles of Thermal Cycling, in LGA socket only one of the corner solder joing had 100% type 3 crack. All other so
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 | 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
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