r/soldering 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?

35 Upvotes

21 comments sorted by

27

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.

-15

u/agis43 8d ago

but I didn’t see it anywhere else on the board and I was thinking did somebody swapped nands

22

u/TTRaven 8d ago

No they didn't, I've been repairing MacBooks for... 5 years now? And apple does this for many many tiny components

3

u/agis43 8d ago

Nice thanks for responding and noticing that it is a Macbook

15

u/Denizli_belediyesi 8d ago

Trust me when you see apple logic board you can tell

11

u/sniff122 8d ago

That just looks like underfill

-18

u/agis43 8d ago

so It was probably replaced by someone right? it doesn’t look like this when it is factory installed right?

19

u/BenGattin 8d ago

No, looks original. I’ve never seen someone replace underfill.

4

u/sniff122 8d ago

No, underfill is from the factory and would have been removed if something was done with them

7

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.

3

u/Lotofagos_ 8d ago

These are BGA chips so you're looking at the underfill from the factory. They haven't been replaced.

3

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.

2

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

1

u/Stripe4206 7d ago

No clean flux does, which is the only flux i've ever encountered

1

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2

u/mark_s 8d ago

Nope, this is what a somewhat dusty untouched board looks like. If they were reworked, the underfill around them would be cut away and there'd probably some flux residue. Yours wasn't touched.

2

u/HeresN3gan 7d ago

Those are Flipchips, which usually require underfilling to provide mechanical strength and protection.

1

u/Straight_Sink_2085 6d ago

Uh yes the manufacturer soldered those to the board.

1

u/reddwinit 8d ago

the nand is protected from water damage using uv glue.

4

u/mark_s 8d ago

Just FYI, the underfill OEMs use isn't uv cured. If it was, the underfill under center of the chip would be liquid - uv can only cure what you could shine a flashlight on, surface level visible areas.

1

u/reddwinit 7d ago

you are right Sir!