Electronics Forum | Fri Feb 19 02:11:11 EST 1999 | Pete Sorenson
| During inspection and test we find leads which do not get soldered. Some are because of insufficient paste, but with others everything looks right. This will only happen on 1 to 2 pins, and it is not isolated to a specific type of ic or location o
Electronics Forum | Tue Apr 20 20:11:58 EDT 2004 | davef
First, how oxidized are these solder balls? Will the take solder using your routine flux / paste? Second, on restoring solderability, the three basic methods you can use to restore solderability on components are: * Highly active fluxes in a retinn
Electronics Forum | Mon May 18 13:18:25 EDT 1998 | Chrys
I'm reviewing my board fab spec. It calls for a minimum SnPb thickness of 50 microinches on HASL PWB's. I've looked at other specs that call out anything from 30 to 80 microinches, and others that just say the copper pad must be covered and soldera
Electronics Forum | Wed Nov 17 11:51:24 EST 2010 | vetteboy86
We have a problem child part. Our company was in a pinch and ordered parts from a broker that had an old date code. The leads are very oxidized, and our reflow process is comprimised. To prove the concept, we cleaned the leads with Tarn X and an aci
Electronics Forum | Mon Nov 26 20:15:50 EST 2001 | davef
Sounds like you are thinking correctly. I'd guess your fab has gotten "smart" and changed your bare board, as you suggest. So, you've got two choices: 1 Rework the QFP. 2 Remove the lower temperature PTH components and solder them to the board some
Electronics Forum | Sat Jun 30 11:28:24 EDT 2001 | davef
Consider using a roll solder with a flux that well matches the residues you can accept to be remaining on the board when you get finished processing. Many people use a no-clean flux cored roll solder for such operations, because they don't want to c
Electronics Forum | Mon Jul 01 13:57:58 EDT 2013 | wpierowski
Recently on one product, I found a white residue on the solder joints only that is more of a gray in color. Our lab told us it was a tin oxide with an unknown organic. This is with a lead free OA paste and it only shows after wash. Has anyone seen
Electronics Forum | Wed Apr 06 21:37:35 EDT 2005 | KEN
Are you saying you have solder balls (as in solder paste balls) at the lead tips (or land tip)? This means your thermal profile is not hot enough. why the sudden cahnge? I will bet the lead frame material was copper and is now alloy 42. sounds like
Electronics Forum | Wed Apr 26 03:32:29 EDT 2006 | saaitk
Hi all, Has anyone any experience they can share with regard to pad dissolution on PTH's on thick boards. We are using lead free SAC305 on both OSP and Immersion silver finishes and are experiencing difficulties when removing and replacing connector
Electronics Forum | Thu Mar 02 07:38:58 EST 2000 | Roni Haviv
Hello, I had experienced this kind of problem; Because the Au film is very thin (flash gold..) it is sometimes porositive and the Ni barrier below get Oxidation. After reflow there seems to be good solder fillets (visualy perfect!) but the leads wit
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