How old are the boards, Steve?   FR-4 or Polyimide?

I've seen old boards do that. Suspected moisture entrapment. Never have seen it
with "new" boards.

Charlie B.




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 Subject: [TN] Blisters or Delamination after Wave...





Hi ya'll!

Well, I'm in onna Saturday...(Months end, you know how that goes!). Just
finished waving a small lot of boards (9 assemblies) and 5 of them came off
the wave with these dime to quarter-sized delaminated blisters, maybe 3-4 of
them on each board, and the other 4 boards looked fine! What would cause
that? Entrapped moisture? The boards were supposedly baked before wave (At
least the traveler said they were). Any ideas?

-Steve Gregory-

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