Electronics Forum | Thu Mar 15 07:49:44 EST 2001 | jax
I am not sure if it is feasible in your situation becuase I don't know enough about your board ( mixed technology, single-sided, etc.... ) , but have you ever considered screen printing paste onto the test points?? JAX
Electronics Forum | Thu Mar 15 17:28:44 EST 2001 | rentreo
Sounds like a problem I ran into recently. In my case it was a problem with via holes which were used as test points on our in-circuit tester. My problem was caused by moisture in the boards. My cure was a 24 hour bake at 100 deg c.
Electronics Forum | Tue Mar 13 18:52:21 EST 2001 | jax
Are the boards in question immersion gold? This could be a process problem at the board shop. If this subcontractor has done good work for you in the past it might be an outside variable causing the problem.
Electronics Forum | Wed Mar 14 10:02:36 EST 2001 | blair
Boards were not immersion gold. They were HASL but I would like to change. What is the prefered surface fininsh for BGA and fine pitch stuff these days? I am starting to ask for Gold/Nickel on FAB Dwgs due to PCB house and assy house discussions.
Electronics Forum | Wed Mar 14 17:26:03 EST 2001 | davef
Most $$-value stuff is dependant on the cost structure of the company. Why not do a small cost study to measure the amount of time your improvements save? Folk in accounting should be able to "rough price" the $$ benefit of your efforts.
Electronics Forum | Thu Mar 15 11:12:45 EST 2001 | slthomas
solder, but flux -> adhesive. Hmmmmm.... Are the chemists working hard to reduce the consequences of these possibilities? And as to Dave's comment about long term reliability issues due to outgassing from the adhesive, double-hmmmmmmm....... Ther
Electronics Forum | Thu Mar 15 11:18:12 EST 2001 | slthomas
That makes us almost even, Dave. I have a hard time believing half of what you say. ;)
Electronics Forum | Thu Mar 15 21:02:20 EST 2001 | davef
Wazis havin' "a hard time believing half of what you say"? I demand a least 90% from peeps!!!
Electronics Forum | Fri Mar 16 13:50:16 EST 2001 | mparker
Shadowing sounds about right to me also. Really dicey experiment to run if you are dropping expensive tantalums just to save a little coin in epoxy and processing time.
Electronics Forum | Fri Mar 16 15:52:22 EST 2001 | blnorman
We screen print epoxy adhesive, place components then run the board through our adhesive oven (2-5 min cure at 150�C). This is in addition to reflow.
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