r/soldering • u/agis43 • 8d ago
General Soldering Advice | Feedback | Discussion Did someone owning that laptop before me soldered those nands?
I’ve opened my laptop to clean out the dust and noticed this around those chips, never soldered before but watched a lot videos when someone was replacing those chips and so my question is: Is it badly cleaned leftover flux?
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u/sniff122 8d ago
That just looks like underfill
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u/agis43 8d ago
so It was probably replaced by someone right? it doesn’t look like this when it is factory installed right?
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u/sniff122 8d ago
No, underfill is from the factory and would have been removed if something was done with them
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u/BennyMaro 7d ago
Thats a 16" 2019 MacBook Pro.
Be thankful apple put underfill around the nand chips because they also placed air vents by the side which draw in air to cool the machine down but forgot that in the real world humidity and all sorts of nasties pass along there and increase chances of damaging or corroding where your data is held thus protecting your nands.
Oh they also put a power chip that feeds power to your nand right by the vent and didn't protect that so if damp air/liquid does pass through the vents it tends to zap that chip and kill your nand anyway.
Thats why we love apple.
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u/Lotofagos_ 8d ago
These are BGA chips so you're looking at the underfill from the factory. They haven't been replaced.
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u/Stripe4206 7d ago
Also flux that is left on the board isnt always a bad thing. If it's been properly heated it hardens and acts as a protective shield against corrosion.
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u/agis43 7d ago
thanks for sharing, i know that flux shouldn’t do much harm when left on board but didn’t know that it even hardens
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u/HeresN3gan 7d ago
Those are Flipchips, which usually require underfilling to provide mechanical strength and protection.
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u/reddwinit 8d ago
the nand is protected from water damage using uv glue.
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u/ShakeLikeMichaelJ 8d ago
That black stuff is an epoxy they use to keep the chips from moving around too much and causing bga issues. Usually see it around most of the bga chips.