Electronics Forum | Tue Nov 27 15:57:58 EST 2001 | mparker
rather than applying jumpers, try thinking it another way. Have all possible jumper connections pre-made by the fab design. Use an exacto or dremel to "open" the undesired paths by removing a bit of copper trace. total flexibility, only one fab make
Electronics Forum | Fri May 08 09:44:23 EDT 2009 | davef
Board fabricators use solder as a resist to protect copper traces from process chemicals. Fabricators remove this resist in later processing. It's possible that board fabrication processing is the source of the tin that you see.
Electronics Forum | Sat Jul 02 10:27:19 EDT 2022 | madisreivik
Hello ! I got exp only with leadfree HASL, but maybe the same problems apply. Also, the leaded HASL has probably lower process temperature. This could be copper, which has settled to the tank bottom. With leadfree, the copper is removed from molten
Electronics Forum | Tue Jan 03 17:38:38 EST 2012 | davef
Here's two ideas fro the fine SMTnet Archives: * On the bare board, during design / layout, the basic shape of the jumper is a 125 thou disc of copper [that of course is eventually covered with whatever solderability preservative we use on the board]
Electronics Forum | Mon Jun 27 06:52:07 EDT 2011 | rpatel28364
Hi All We are facing problem with solderability of BGA connector. After Xray we have found open under BGA connector. After removing from PCB it seems some copper pads are still gold. We are not sure why this is happening. We have 5 thou stencil and
Electronics Forum | Thu Jul 31 15:41:23 EDT 2003 | davef
Q: Could any of you guys tell me what exactly is this greenish thing ? A: No, but is not copper oxide. Copper oxide is brown, the color of a penny [here in the US] or an untreated copper laminated trace on a board. Many copper salts are greenish in
Electronics Forum | Fri Apr 15 09:56:17 EDT 2022 | winston_one
Thank's Dennis. I'm also now think in this direction. Process was adjusted and soldering are good. But one from five boards can have this effect with bubbles and strange uneven distribution of solder inside the barrel. Probably copper is too thin and
Electronics Forum | Sun Jun 27 06:27:15 EDT 1999 | Vic Lau
| I am looking for a way to clean solder off of QFP packages. I'm thinking a chemical method would be easy, as long as the chemistry doesn't attack the leads themselves, or the package. | Any suggestions? | Dear Matt, I have a customer, who is com
Electronics Forum | Mon Jun 28 14:36:34 EDT 1999 | John Thorup
| | I am looking for a way to clean solder off of QFP packages. I'm thinking a chemical method would be easy, as long as the chemistry doesn't attack the leads themselves, or the package. | | Any suggestions? | | | Dear Matt, | | I have a customer
Electronics Forum | Thu Sep 04 05:18:45 EDT 2014 | sasa29
PCB Manufacturing demands preparation of design well in advance. The finalized designs are fed into the systems and the production is carried away. If the boards are of small sizes, multiple boards are made on a single large board and separated into
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