Electronics Forum | Fri Sep 12 17:58:30 EDT 2008 | robinj
Can someone let me know what is causing this black coloration around the pads? It is on the edge of all pads all over the board. The surface finish is OSP. I don't have any solderability issue. But the stencil printer is having trouble with picking u
Electronics Forum | Mon Aug 29 22:48:09 EDT 2011 | davef
Rich Here's what Humiseal says: Thermal Properties The coating must be able to withstand localized thermal 'hot spots' generated by components. High temperatures can cause short-term changes in coating characteristics, such as softening and lowered e
Electronics Forum | Fri Sep 02 16:30:02 EDT 2011 | duso02
Rich That is a standard reaction with Humiseal 1A33, nothing to worry about. Find a board that was coated over year ago and had been heated up at all and it will be an amber color. It does not violate the IPC for discoloration. We have coated boards
Electronics Forum | Sun Jan 20 21:03:34 EST 2002 | peterson
Hello everyone! We just completed some 16-layer boards and noticed (after wave soldering) that there are some unique, white-ish discolorations. It looks as if someone layed their finger at weird angles on the groundplane areas. It is NOT finger prin
Electronics Forum | Mon Oct 28 08:54:57 EST 2002 | Chris Lampron
Good Morning, I think that the use of No clean at SMT and the use of WS at wave is counter productive. For the most part, you will get better results using WS at SMT. If you use No Clean, and then are forced to run this thought a water wash as a req
Electronics Forum | Fri Aug 08 08:00:46 EDT 2003 | davef
Matt: You're correct. Do not mess with these boards. If the immersion tin [imm tin] is discolored, it will not solder with routine processes. Ask your customer to return the boards to his / her fabricator and have the imm tin replated. The fabri
Electronics Forum | Mon Jan 07 13:28:56 EST 2019 | slthomas
Hi, I would like to try to help, but I think I need help in understanding your problem better. 1) do you see any discoloration of solder joints on the first side, after first side reflow? 2) after second side reflow, are solder joints on just the
Electronics Forum | Tue Oct 26 12:18:53 EDT 1999 | Gary Kemp
We are having a discolorization problem with the gold fingers on our PCB's. I have been made aware that there is a gold touch-up paint (masking) that is available. Would anyone know where I can get my hands on some of it? Any help would be appreci
Electronics Forum | Wed May 20 15:10:35 EDT 1998 | Dave F
We notice that DI water seems to tarnish or discolor the metal packaging on crystals and DIN connectors. Our marketing types like the shiney metal surfaces. We don't want to hand solder these parts after washing. Any suggestions? Dave F
Electronics Forum | Tue Jul 27 13:48:45 EDT 2004 | Ralf
Hi Recently i have noticed that after reflow (hot air oven) on the solder lands without components but with solder(screen printing) there is discoloration. It looks like gasolin spilled on the wet road (rainbow). Any idea and reason Ralf
