Hi Technos,

I can really use your expertise to clarify one of my recent worries.

I have a batch of boards on which, after the first reflow, the slikscreen
marking turned pink, from the immaculate white it was displaying before. Not
that I don't appreciate a little of "pynk" inside the gray "walls", but I
wonder why did this happen.

Out of a batch of 20, 5 changed color. The boards are high complexity, ultra
high density, extremely high-end, big $$ value, etc. Since this is not the
first time we build these assemblies, I can't blame it on the reflow profile
or a reaction with the flux of our no-clean paste.

I suspect a sort of insufficient curing. Am I right? If so, and now's the
worry, could this hide some other, more detrimental, flaws of the PCB?

Many regards,
Ioan

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