Electronics Forum | Wed Jul 01 12:26:52 EDT 2009 | ewchong
can anyone suggest possible causes or further analysis for the lifted pads in attached picture. thanks.
Electronics Forum | Thu Jul 02 13:10:22 EDT 2009 | kpm135
On first glance it looks like those particular pads were not attached to any traces. If I had to guess I would say that your rework profile got hot enough to melt away the glue holding the pads to the board and they came away with your part when you
Electronics Forum | Thu Jul 02 16:01:57 EDT 2009 | ewchong
thanks kpm. agree the cause of those pads lifting. all of them were no connects so they cannot be the cause of the electrical failure. when the bga was removed, all the solder balls on the pcb turned into conical shape due to the separation, except
Electronics Forum | Tue Jul 07 08:42:49 EDT 2009 | ewchong
kpm, you are probably right. under magnification those two pads show some exposed copper which means that they were contaminated or had insufficient solder paste before reflow.
Electronics Forum | Tue Jul 07 05:55:34 EDT 2009 | kpm135
I agree with your assessment of the two pins with irregular solder. The head-in-pillow or broken joint are both probable events for your defect. At this point in the process it will probably be difficult to pinpoint the exact cause. If it was a broke
Electronics Forum | Wed Sep 29 09:29:47 EDT 2010 | swag
Take a few parts from the reel and look close at the parts to make sure the bottom surface of the leads is below the bottom surface of the body.
Electronics Forum | Thu Sep 30 11:30:46 EDT 2010 | babe7362000
Take a few parts from the reel and look close at > the parts to make sure the bottom surface of the > leads is below the bottom surface of the body. Yes I did that and they are below the body. I found the problem I think. The solder mask is abo
Electronics Forum | Mon Dec 22 12:41:17 EST 2003 | Marc Simmel
No clean solder paste. One further observation ... the parts have a metal shell and are 'floating' high on the paste. Though there is wetting on the metal shell, it doesn't seem to sink as far as it should and this could be lifting the soldertails f
Electronics Forum | Wed Sep 29 08:26:03 EDT 2010 | babe7362000
We are Currently running a Board and it seems that the SOT-223's on the bottom side have flux and water trapped under the part. Nothing has changed in our process and this is the only board that it is happening on. We are using Kester R562 water wa
Electronics Forum | Mon Dec 22 15:35:18 EST 2003 | davef
Marc: Please be more explicit. * When you say, "parts have a metal shell"; are you talking about the component leads or the component body? What is the metal, what is it appearance, and what are it's implications? * When you say, "the parts have a
