Electronics Forum | Sat Nov 18 21:20:58 EST 2006 | Fer
Dave, May I ask where did you find the 1.5%, or the goal of .005" (or .007") per inch? The IPC-A-600 bow and twist standard calls for a .75% based on the calculation of the test method TM-650, method 2.4.22, which calculates the percentage based on
Electronics Forum | Mon Feb 19 17:34:02 EST 2007 | GS
Thank You Pavel and Dave, Unfortunately I do not have IPC-4554. Anyway I 0.6-1.0umm is what I remember, and confirmed by reading also through leterature available on google. I was just going to understand if it possible to obtain more thickness
Electronics Forum | Wed Aug 17 14:18:11 EDT 2005 | ppwlee
Dave, Answers to your questions: * From your pictures, the white residue appears to be only on the solder mask. Is that correct? If not, what is the location [eg, solder, nonsolder/nonmask areas] of the residue that doesn't show well in the pictur
Electronics Forum | Sun Jan 31 22:55:33 EST 1999 | Dennis O'Donnell
| | Hello Netters, | | | | I need some info, Earl or Dave, I have a PCB that exhibits a white layer on solder side. It does not appear to be surface residues (IPA has no effect), but looks like its under solder mask. My first guess is that the LPI
Electronics Forum | Wed Feb 03 04:44:43 EST 1999 | Jeff Sanchez
| | | Hello Netters, | | | | | | I need some info, Earl or Dave, I have a PCB that exhibits a white layer on solder side. It does not appear to be surface residues (IPA has no effect), but looks like its under solder mask. My first guess is that t
Electronics Forum | Thu Feb 10 10:28:56 EST 2000 | Russ
Okay, Okay, here is the rest of the story! These boards were definitely plated, reworked to HASL, The component that is the most succeptable is a 160 pin QFP .5mm pitch. This component has nickel/iron lead frame. Significantly reduced apertures (1
Electronics Forum | Wed Dec 20 22:24:03 EST 2000 | Greenman
Dave: In terms of heat transfer, air is 78% nitrogen, and the remainder is mostly (20.9%) oxygen (roughly the same molecular weight as nitrogen), with a bit of argon (0.9%), CO2, hydrogen, monosodium glutamate etc. So you would expect virtually no d
Electronics Forum | Wed Dec 20 22:25:26 EST 2000 | Greenman
Dave: In terms of heat transfer, air is 78% nitrogen, and the remainder is mostly (20.9%) oxygen (roughly the same molecular weight as nitrogen), with a bit of argon (0.9%), CO2, hydrogen, monosodium glutamate etc. So you would expect virtually no d
Electronics Forum | Wed Dec 20 22:26:01 EST 2000 | Greenman
Dave: In terms of heat transfer, air is 78% nitrogen, and the remainder is mostly (20.9%) oxygen (roughly the same molecular weight as nitrogen), with a bit of argon (0.9%), CO2, hydrogen, monosodium glutamate etc. So you would expect virtually no d
Electronics Forum | Tue Sep 12 11:55:30 EDT 2000 | Mike F
In general I agree with Dave and Chris, but some parts have leads that can't be clinched (connectors, some header sticks, etc.). If the problem part has not been a floater in the past, then check the lead finish and your flux application. A bad finis