Electronics Forum | Fri Apr 10 13:25:08 EDT 2009 | jefflkupkt
Layer 2 is the ground plane layer of a 4 layer board. After installing a 2.5 mm DC power jack and 0.1 center SIP header by hand, the ground pin disconnects and causes an open. My board supplier said they passed Electrical Test. Prepreg was within
Electronics Forum | Fri Apr 10 18:51:39 EDT 2009 | boardhouse
Hi Jeff, Your board supplier could be correct in this way. The board could have had just a hair left of copper on the circuit, which would hold up under the electrical test process, but once you powered it up, then there was enough juice to burn th
Electronics Forum | Mon Apr 13 12:06:53 EDT 2009 | jefflkupkt
BoardHouse, Thanks for the reply. The board supplier did cover the cost of the bare boards. Five years ago I saw a different part pass ET only to fail at final assembly test as well. One engineer called it "acid trap" on the inner layers where the
Electronics Forum | Tue Feb 25 06:06:11 EST 2020 | hexton
I am currently weighing up my options for resistors that will be fitted to a fully assembled PCB (PTH&SMT). Do I omit the stencil apertures leaving exposed pads (ENIG) so they can be hand soldered with fresh solder. Considering shelf life for soldera
Electronics Forum | Wed Feb 26 13:26:24 EST 2020 | rgduval
I'd agree with getting a stencil fully cut, and taping the pads you don't want paste on. But, I'd also check with the people that will be doing the hand soldering to see what they prefer. Some people prefer soldering on bare pads, some prefer solde
Electronics Forum | Tue Feb 25 18:36:03 EST 2020 | emeto
Flat surface is the number one choice for fresh part soldering. We did not discuss details about resistor size and location, but to keep them flat I will suggest no apertures on the stencil.
Electronics Forum | Wed Feb 26 07:07:19 EST 2020 | dontfeedphils
"One caveat with ENIG is sometimes washing with hot DI water can effect solderability later on." How so? (Genuinely curious)
Electronics Forum | Tue Feb 25 10:30:02 EST 2020 | richardcargill
If you get the stencil made with all apertures included then you can blank some off with sellotape. Saves you buying 2 stencils should you require them machine fitted in the future
Electronics Forum | Tue Feb 25 11:56:33 EST 2020 | slthomas
I think I'd opt for a stencil with everything already cut and then tape it if that didn't screw up your stencil gasketing. Then you just have to define the process for adding the optional parts and you can decide to use those apertures or not.
Electronics Forum | Tue Feb 25 06:18:55 EST 2020 | spoiltforchoice
First question would be why are you hand soldering these resistors? I would expect ENIG to be perfectly solderable after reflow and quite some time later. If you leave the apertures out of the stencil and then decide to automate fitting them, you'l
