Electronics Forum | Fri Jun 07 11:08:34 EDT 2019 | gregoryyork
OK good if you get really close to the two small solder balls trapped in that greasy waxy residue and carefully turn the balls over you should see that they are flat on the side stuck to the solder resist.
Electronics Forum | Fri Jun 07 11:10:08 EDT 2019 | teejsd
We also have a Foresite C3 for spot testing for ionic contamination. I didn't use it at this spot, but used it some other spots around the PCB that showed this color change and with our C3 we were passing IPC standard for ionics. But I was wonderin
Electronics Forum | Fri Aug 23 02:47:03 EDT 2019 | sssamw
Even 93% humidity, it will has no condensed water film inside or on PCB, it will have no ECM or CAF, for such consistent 40℃ temperature.
Electronics Forum | Fri Jun 07 12:34:30 EDT 2019 | teejsd
C3 just uses heated DI water that it applies, then pulls back into a disposable cartridge. Machine then applies a 10V charge to the sample & measures leakage current(nA,I think) over time(sec). If the leakage current is high enough/fast enough, you
Electronics Forum | Fri Jun 07 12:44:55 EDT 2019 | gregoryyork
These residues are extremely water miscible BUT you will probably need the extraction of heated IPA/Water to get the porous resist to release the residue quicker than it would do releasing it naturally in the field. Why dont you try to soak the circu
Electronics Forum | Fri Jun 07 14:14:24 EDT 2019 | teejsd
Yes neither our HPLC IC nor our C3 could detect any concerning levels of ionics. Soaking over a weekend sounds like a good idea, though I may still need to cut the board down to fit our Kapak bag size. And get our silicone coating off the surface. K
Electronics Forum | Thu Apr 04 20:21:57 EDT 2019 | teejsd
We're testing this PCB in 40C 93RH to see if we get ECM or CAF. We have failure. I traced it back to the vias on the left (signal & gnd)if I can get the picture to load. We have not yet confirmed or denied CAF. I am wondering if I should be concer
Electronics Forum | Fri Jun 07 11:19:14 EDT 2019 | gregoryyork
If you have soldered with HASL finish then the worrying chemistry will be more like NON IONIC. They sit there and attract moisture like mad and any chlorides they hold ionize in the moisture attracted and cause electromigration or SIR issues. They ca
Electronics Forum | Mon Jul 23 08:35:33 EDT 2012 | grahamcooper22
The lower the RH in the MBB the better for all moisture sensitive devices. Maintaining less then 5% will mean no parts of between 2a-5a MSL will need drying before use. The calculation uses 10% because it is a sensible amount of desiccant to use base
Electronics Forum | Fri Jun 07 11:39:33 EDT 2019 | gregoryyork
I feared so. The only thing to be done is to tell the PCB manufacturer to increase the Thermal cure so dont set the oven to 150C but to 170C and actually measure the middle board and once it hits 155C then give it an hour cure from then. Also insist
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