Electronics Forum | Thu Dec 26 12:12:55 EST 2013 | igorfo
Dear Friends, I need your help to understand requirements and measurement methods for bow and twist of assembled PCB (PCBA have and SMT and TH components). I already check all posts on the site but didn't found any related to my question answers.
Electronics Forum | Fri Jun 11 03:39:26 EDT 1999 | Gyver
| | | | Hello all! | | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We doubt
Electronics Forum | Mon Jun 14 14:30:42 EDT 1999 | Deon Nungaray
| | | | | Hello all! | | | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We d
Electronics Forum | Fri Jun 11 01:40:40 EDT 1999 | Gyver
| | | Hello all! | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We doubt it'
Electronics Forum | Mon Jun 14 09:16:58 EDT 1999 | Adam Pratt
| | | | | Hello all! | | | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We d
Electronics Forum | Fri Jun 11 04:38:05 EDT 1999 | Gyver
| | | | | Hello all! | | | | | Recently we got a problem about the Funtional test. Some boards passed tests by using the auto-fixture(vacuum), but failed by using manual test fixture(need to plug CPU, DIMM etc.). The error symptom is no picture. We d
Electronics Forum | Sat Feb 01 09:01:14 EST 2003 | davef
It sounds like your board is "dome shaped", some call it "cupped". If so, this is more of a twist than a bow. Before moving on, if we receive a board that is so torqued that we can't figure-out how to measure it, we reject it. Go back to your TM-
Electronics Forum | Wed Jan 29 14:22:56 EST 2003 | russ
Most bowing I see is caused by an asymetrical layer stackup of the PCB. (different copper thicknesses throughout the stackup) e.g. for a 4 layer board - 2 oz. copper on layer 1, 1 oz. copper on layer 4, etc... I would doubt that is the V-score since
Electronics Forum | Thu Aug 10 13:12:10 EDT 2000 | Bob Willis
You may care to review the following from my Circuits Assembly page on line. "HOW FLAT IS FLAT AND DO WE NEED FLAT CIRCUIT BOARD, YES WE DO ? As production problems go there is one that keeps reoccurring time and time again. The blame is usually di
Electronics Forum | Sun Aug 08 11:15:32 EDT 1999 | Earl Moon
| | Mike, | | | | Got your message and those of others concerning PCB fab supplier evaluation and qualification check lists, etc. I have a severe problem here in WI as I can hardly access the internet, and when I do it is cut off abruptly for no goo
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