Electronics Forum | Thu Aug 28 04:07:46 EDT 2008 | kelson
Hi robinj As you have mentioned, if the color is yellow usually it is caused by moisture left on the boards from poor drying after immersion silver. However, our boards were received from the supplier and the changes happened in our side. So, what di
Electronics Forum | Wed Sep 03 11:42:21 EDT 2008 | robinj
If the tarnish is really dark, it is very difficult to remove. Since it is yellowish it is only in the early stages. Replating will definitely work. I have used sulfuric acid based cleaners to remove this yellowish color. But rinse well and dry quick
Electronics Forum | Tue Aug 26 09:33:04 EDT 2008 | wavemasterlarry
If this board is waved soldered than you may want to look at the wave causing the BGA to reflow a 2nd time when it goes over the wave. The board bows down and the the joint liquidfies and then hardens before the board fully goes back to flat which c
Electronics Forum | Tue Sep 09 16:00:07 EDT 2008 | ppcbs
We always bake our loaded boards before any BGA rework is done. 12 to 16 hours at 100 c. We have had incidents in the past on loaded boards where 125 c has melted parts and the occasional low temp BGA trays. 100 c has proven safe for the past 10 y
Electronics Forum | Thu Sep 11 14:20:07 EDT 2008 | pcbrown57
Is there any criteria or limitations for SMT pcba's? We have boards in stock that we built and a customer wants to know what our procedure is for "storing" these boards which will have a few through-hole modules soldered to them after they get pulled
Electronics Forum | Fri Sep 19 02:38:12 EDT 2008 | grantp
Hi, We would like to do low volume large boards, and does anyone know what options there are for stencil printing larger boards. The board we are doing is 412mm x 685mm so it's quite large. Pick and place is ok, just stencil printing. Is there some
Electronics Forum | Tue Sep 23 07:27:31 EDT 2008 | realchunks
Do not wipe the board at first before putting it in your cleaner. It will leave more paste in your tank, but you won't smear it into every corner of your solder resist. We found that only our stencil cleaner would clean a board properly and leave n
Electronics Forum | Mon Oct 20 14:28:09 EDT 2008 | jdumont
Yup, just read that in the link Patrick sent. Thanks again... Im going to have everyone screen the boards for this carefully before processing. I have also sent the board manufacturer an email to get their comment on the matter. No PCB vendor thinks
Electronics Forum | Thu Oct 23 23:38:48 EDT 2008 | pathakvj
We have 8 layer HASL PCB. We saw molten solder blobs / balls on op side of assembled PCB. (to check, if this was a bare board problem), We passed bare board as received thru, SMT reflow oven and saw solder balls on top side of board. What could be th
Electronics Forum | Fri Oct 24 06:55:48 EDT 2008 | clampron
Good Morning WS, If you experieced the solder balls after reflow of a bare board through the oven, then the source of the solder is either the oven or the board. I have had boards with untented via's that were HASL'd that had entrapped solder and fl
