Electronics Forum | Wed Sep 26 12:16:44 EDT 2012 | bwjm
Hi Guys,recently i am facing an issue. Refer to the attached photo. This PCB is high RF speed, gold immersion single layer. After reflow, my solder seems to have black stains on it. I tried with SAC305 paste water soluble and no-clean, both results a
Electronics Forum | Fri Apr 16 13:22:48 EDT 2010 | stepheniii
Have you tried running a few bare boards through the oven? If there is no flux on them and you still get the "stains" then I think you can eliminate the flux as the cuprit. And I've been told that white is the second most difficult solder mask colou
Electronics Forum | Fri Jul 10 07:34:00 EDT 2020 | elijah
From the poor bonding strength of the board, the surface quality problems of the board are divided into: 1. The cleanliness of the board surface; 2. The problem of micro graphite (or surface energy) on the surface. PCB circuit board proofing Youke bo
Electronics Forum | Fri Apr 16 10:49:55 EDT 2010 | davef
Your picture is not very useful in conveying the stains. Could the stains be a delamination of the board?
Electronics Forum | Tue Oct 21 22:25:35 EDT 2014 | richardciccarone
Thanks for the input. I read that paper. I'm not convinced the Pb stabilizer and bath MTO's are a cause of the Black Tar defect. If that were the case, given the history of Pb stabilizers and ENIG, I would have thought that there would have been many
Electronics Forum | Thu Apr 15 14:09:48 EDT 2010 | richardli
We found stains on the boards come out of reflow oven. The board itself color changed to yellowish from white . We understand discolor soldermask due to high temperature. This can be acceptable by our customer not the stains. The stains look like wa
Electronics Forum | Fri Apr 16 12:17:51 EDT 2010 | richardli
We have asked the supplier use whiter soldermask taking more heat. We also asked the board supplier to double coat board with soldermask. All these tries failed. We are wondering if the stains are flux contamination.
Electronics Forum | Fri Apr 16 11:51:26 EDT 2010 | shawnvike
Looks like a simple variance in the solder mask discoloring. Shawn
Electronics Forum | Sat Nov 25 18:45:19 EST 2000 | Ashok Dhawan
I am getting black spots / stuff while I run gold finish PCB through reflow soldering process using NC solder paste.The affected spots have intermetalic as black in color. Does not solder very well. I did look at the archieve but could not find info
Electronics Forum | Mon Jul 28 16:32:45 EDT 2003 | itempea
Mant, we are reliably replacing BGAs of all sizes and pitches on ENIG. The black pad is not something created through rework, but a defect that the PCB has from the very beginning. Ioan
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