Electronics Forum | Wed Jul 29 21:16:17 EDT 2020 | SMTA-64387706
Hi, I have a PCB that works fine when tested before conformal coating with HumiSeal 1B73. It seems like the CC is causing electrical issues. We brush it on, so it is a bit thick. After curing we are getting QFNs that do not seem to connect well and a
Electronics Forum | Wed Aug 24 12:37:38 EDT 2011 | hussman
Hello all, We just got some board back from thermal shock and we found that several of the 2512 resistors opened up. Actaully the solder joint cracked away from the board. All other coponents look great. Boards were good before test. 10 layer bo
Electronics Forum | Thu Aug 20 07:11:25 EDT 2020 | sssamw
What your said looks like a acrylic coating thermal expansion causes small solder joint crack. Do you cure coating with heating, or heating after curing? Solder joint crack while you see resistor and QFN trouble? Clear and detail description of your
Electronics Forum | Thu Mar 14 09:07:26 EST 2002 | cfraser
I can not tell you what the actual stress limits are. I can tell you that de-paneling PCB's by hand is a very poor choice. I have seen numerous accounts of cracked caps, resistors, and LED�s due to incorrect de-paneling procedures. I would recommend
Electronics Forum | Thu Mar 30 11:10:43 EST 2000 | Gary Kemp
Is the same marking protocol used when identifying 0603, 0402, etc.. components? For instance, would a 27.4K ohm 1% resistor still have four (4) characters to identify if the body color is black? Any feedback is appreciated. Thanks.
Electronics Forum | Fri Dec 13 10:06:05 EST 2013 | davef
For vertical mounted, axial leaded components; the standoff from the land to the component body should be 0.4mm[0.016in] to 1.5mm[0.059in]. Right?
Electronics Forum | Tue May 25 07:03:34 EDT 1999 | Milan Z.
After reflow proces in convection-IR oven we find broken body of SOT23 elements. There is no problems on other elements (SOIC, chip R,chip C, etc) Where is the problem? Thanks in advance!
Electronics Forum | Mon Oct 04 07:48:34 EDT 2010 | scottp
When you break them where is the failure? Is it the solder joint (doubtful), the part termination, the body of the part, or the board? If in the solder joint, is it in the bulk solder or intermetallic? If in the part, what direction is the crack?
Electronics Forum | Mon Aug 29 12:45:01 EDT 2011 | scottp
Now with lead free in the automotive world we include 1206 chips for the same reason. A ceramic 2512 only lasts a few hundred cycles of -40/+125C with lead free solder. A plastic bodied 2512 can go several thousand.
Electronics Forum | Mon Nov 23 19:20:18 EST 1998 | Kevin
A buddy of mine has problems after depaneling double sided pre-scored PCB's. Resistors near the edge, after put into the slice and dice machine contain micro cracks. He's checked for them before and after depaneling. We figure it is the sectioning
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