We recently received a prototype batch of 4 boards and experienced 4 for 4
failing test. Our techs sprayed down certain chips with Freeze Spray and
the board began working properly, at least for a short period of time. I
have checked prior tech net postings and have found fantastic responses as
to why Freeze Spray can damage a the IC or board, but can anyone explain why
they would begin functioning properly. Being a rookie component engineer I
can fully understand the issues related to freeze spray, but out techs and
design engineers are just going to point the finger since their units work
when sprayed. To further complicate the matter the chips that are being
sprayed are not all the same manufacturer and I can easily rule out a
component failure. Our senior engineer thinks that it may be timing related
since the main circuit being froze is the Altera PLD (20K400E) and related
circuitry.
Can anyone defend the use of Freeze Spray?
Can anyone present a logical failure mechanism?
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The best Freeze Spray argument to date was Werner Engelmaier's:
http://jefry.ipc.org/scripts/wa.exe?A2=ind9907&L=TechNet&D=0&m=23823&P=55370
However this points to failure after spray not the opposite.
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