Electronics Forum | Fri Nov 16 10:53:30 EST 2001 | Carol Stirling
Hello Everyone, Our board supplier changed our board surface finish on a prototype to flat solderable tin (FST) because of the PWB thickness (.125"). The pads seem to be contaminated, particularly on second side pass through reflow. The solder appea
Electronics Forum | Thu Nov 22 08:30:59 EST 2001 | krs
I have heard of this but do not have direct experience. Immersion tin is susceptible to moisture absorption particularly after washing off solder paste. So it sounds like your boards are picking up the solvent off the screen. Water rinse or degrease
Electronics Forum | Mon Nov 19 20:15:39 EST 2001 | davef
Now, that is one thickass board!!! The rant first: If our �board supplier changed our board surface finish on� anything without our approval, the board supplier would be an �X�. Life has enough surprises. And of all the flat finishes available, h
Electronics Forum | Thu Jan 20 13:56:51 EST 2022 | stivais
For me it seems that the board is already assembled & soldered. Before assembling the board had been (poorly) washed (misprint perhaps) and the spots are just melted solder paste. Aren't those solder balls in the grooves between the pads and solder
Electronics Forum | Fri Jan 21 12:36:52 EST 2022 | stephendo
Like I said a lot of people don't tape the gold fingers the first time they run them. After that they make sure the fingers get taped up because solder gets places you don't think it does and once it touches gold, that gold is contaminated. How do y
Electronics Forum | Wed Jan 21 16:55:22 EST 2004 | patrickbruneel
Hi, Are you testing bare boards or soldered boards. Are the test probes in contact with soldered pads or contacting the copper with the osp coating (not soldered). If you could clarify this it would be easier to give some hints for probable causes.
Electronics Forum | Fri Jan 21 06:35:51 EST 2022 | stivais
"Manual washing" of a misprint board basically is smearing of printed solder paste all over the board. And trying to remove (wipe off) it afterwards. So for me it would not be any surprise that the solder paste ended up on the pads where it was not i
Electronics Forum | Fri Jan 28 13:49:48 EST 2022 | jseewald
That is correct. This looks like a board that was printed then wiped but not washed. Solder spheres left out on an unsolderable surface will just sit there like this or coalesce into solder balls. Nothing in the picture indicates an issue with the
Electronics Forum | Thu Jan 20 21:37:18 EST 2022 | charliedci
I agree it looks like that, but no solder has been on this area. We are asking the board house to get their input.
Electronics Forum | Thu Sep 30 15:46:22 EDT 2010 | vetteboy86
Hi Folks, I'm looking for detailed information about the different composition of circuit board pads. We have been experiencing some issues with our solder, and I would like to know the differences between compositions. I do know that we ran a cust
