EEVblog #1222 - Apple's MacBook Design FAIL - Who's To Blame?

A deep dive into how and why Apple's post 2016 MacBook Pro's fail after water ingress, and the poor design decisions that lead to it. Which engineer at Apple is to blame? Or is anyone actually to blame?
The PCB and product design process, the often siloed design jobs, and failure mode analysis
Includes a demo of water hydrolysis on a PCB.

#Apple #MacBook #Design

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[rossmanngroup]

For those interested, this design began in 2016, and has persisted throughout 2017, 2018, and 2019 with no changes.

[pldaniels]

Thanks for the mention there Dave - will have to send you a licence of FlexBV.

[rasz]

Putting ground pin next to BCKL was standard Apple practice ... until this model, but as Tim Cook wrote in a letter to investors this January: "People Bought Fewer New iPhones Because They Repaired Their Old Ones".
BTW Backlight circuit fuses in Apple devices almost never trigger, connectors melt/go up on fire first :)

[rich]

I thought this was a louis rossmann video. I got bamboozled. I am subscribed to dave as well, so I'm not mad.

[OldWhitebelly]

If anyone is to blame, it's the customer that refuse to hold the company accountable. I know someone who, after TWO Apple laptops burned up on them, bought a third. No warranty stuff here; they bought three.

[mah]

Former Apple engineer here. I can well imagine how this happened. Young engineer joins the company, so the team gives him something simple to start with: draw the schematic for the display flex circuit--seems easy enough. He/she correctly puts the high current pin on the large contact, and then proceeds to label the signals starting from pin 1. There's no design rule forbidding this and nobody points out that this is sub-optimal, and the prototypes get built. The reliability team tests these units, and they have their hands full ironing out issues that happen in nominal use cases (e.g. butterfly keyboard). The product doesn't claim to be waterproof, so water ingress is low on their priority list. When they do test water, all sorts of things go wrong, and the display connector frying is just one of them, so no one pays this particular failure too much attention.
The boards eventually go to production, and now it's a pain to fix, because you'd have to change both the display and the motherboard, and go through all the testing again to make sure your fix didn't break something else. Also, you'd have to set up your supply chain to manage the different configurations, etc. Realistically, for relatively small issues like this, the next chance to fix it will be when they change the display, which would be a major updatel. Hopefully the engineer who drew that schematic is watching this, and will learn from it for the next design. But all that talk about planned obsolescence is just ignorant--we tried to make these as reliable as possible so we wouldn't get calls from the factory on a weekend complaining about failures.

[mcameron]

Dave and Louis in one video? I've never clicked so fast.

[paulyoung]

Anyone can make a mistake, happens to all of us. What happens next is important, here Apple has not addressed the issue that is the real problem.

[terrance_huang]

The dark compound appears like "carbon", but actually, most of them are copper oxide or other copper compounds.

[Cynyr]

mechanical engineer here: why not just a small dab of di-electric grease in the connector to keep out the water in the first place? It's pretty common in cars, and industrial equipment that needs to be rain and/or submersion proof.

[bgills]

I think I would have the nearest pin be a sense pin. If it sees any voltage it immediately shuts off the backlight, and keeps it off until the computer is shut off. The next nearest pin would be a ground pin to shunt any actual power to where it won't damage anything else.

[chrismr]

Condensation: Often missed as a source of water damage. Take something that's been outside in the cold and put it in a warm (and therefore more humid) room and you get water everywhere. Keep a slab of aluminium in the fridge and then take it out to show someone condensation damage, quite an eye opener

[PERILEX]

In general, separating power and signal lines as good as possible is one of the most basic things anyone working with electronics should know.

[brumbymg]

I have seen the "Silo" structure in software development - and the idea of kicking things "over the wall" so it becomes someone else's responsibility is all too easy. I've never liked it.

[RandyLott]

I just don't understand how you can design a proper schematic without knowing how you are going to lay out the board(s).

Similarly, I can't understand how someone could place and route a board effectively without understanding the functionality of the circuit. At least for me, I couldn't deal with other people's bad habits or lack of foresight. Thankfully, I am able to have control over my entire design from start to finish. It's a lot more work, but I like it that way.

For the price and attitude, Apple should not be having these issues.

[oswaldjh]

The electronics design firms that I worked for all had environmental chambers to test products for temperature and humidity sensitivity at different air pressures.
They also had shaker tables that could dislodge the large heavy components on power supply boards and toss them into the air.
Testing is fun, Apple should try it.

[MoreCharactersThanNeeded]

I klicked on this because I thought it was a new Louis Rossman video. Turns out it was something even better. Got both of my favorite channels in one =)

[thebishtable]

It's a bit of a tangent, but it'd be cool if you could test the effectiveness of various conformal coatings against moisture with your simple 50v test.

[johncrunk]

I just watched Paul replace that mux chip. I'm in awe of anyone who can herd those tiny little balls into place and actually fix something. Bravo!

[taith]

You two should have chat about it, but other laptops have their boards wrapped in foil and case/keyboard are designed in a way to route the liquid trough the holes in the bottom of device, where in Apple your sneeze can shoot trough keys and land directly on tracks.