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Macbook charger teardown: surprising complexity inside Apple's power adapter

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Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#241

Post by PhantomGremlin »

Alupis wrote: post #215
Bud wrote: post #210

Earlier quoted context omitted.

Alupis: I should have clarified that I was speaking from my own personal experience with supporting hundreds of laptops. You're right. I admit that my evidence is anecdotal, but there is a lot of it. As others have already pointed out, no, MagSafe is not gone. Dell's chargers, as do many other PC chargers over the last 10 years, routinely break the charging port on the computer if they get yanked on too much, which i…

> from my own personal experience with supporting hundreds of laptops I'm curious to how much hardware support goes into this, since most Apple machines are designed to not be support friendly (eg. non-replaceable and/or difficult to replace normal wear-n-tear components). > routinely break the charging port on the computer if they get yanked on too much Yes, most laptops have this issue, although it's not nearly as…

quite a few services for $75 inclusive of the DC jack ... Apple's cheapest adapter with magsafe cable on it is $79.

That's an oranges-to-apples comparison. :)

It's not fair to compare 3rd party repair services to a new Apple product. There are also 3rd party repair services for Apple chargers. For example, I know these guys will repair them: http://madmacsoforegon.com/Mad_Macs_of_Oregon/Welcome.html

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#242

Post by Udo_Schmitz »

Bud wrote: post #122
throwaway420 wrote: post #30

Despite the visual appeal of their products, Apple normally does a very good job with prioritizing function over form except in this case with the charger wire being so fragile and thin. I know I'm not the most careful and delicate person in the world, but the failure rate here is ridiculous compared to other similar products I own. The end of the cable gets frayed every single time. Otherwise, Apple makes ridiculous…

I support around 300 Macs for work. In my extensive experience, the deal here is that people are FAR too rough and careless in winding up those charger cables over and over. Apple HAS implemented strain relief here and done their best to make the points of failure less vulnerable. Here's a tip: Instead of yanking the cable at a 90-degree angle and winding as tightly as possible, let the cable come out of the charger…

You know what I think? It’s not our carelessness but the plastic they use for the cables: I own 2 chargers for my MacBook. I do the loop for the charger I carry around. The one I leave home on the floor never got wound up. It looks like this after about two years: https://twitter.com/Udo/status/667295383299579905

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#243

Post by shaneofalltrad »

Alupis wrote: post #161
Bud wrote: post #122

Earlier quoted context omitted.

I support around 300 Macs for work. In my extensive experience, the deal here is that people are FAR too rough and careless in winding up those charger cables over and over. Apple HAS implemented strain relief here and done their best to make the points of failure less vulnerable. Here's a tip: Instead of yanking the cable at a 90-degree angle and winding as tightly as possible, let the cable come out of the charger…

Way back in my computer repair days, I used to commonly see macbooks with horrendously frayed and/or just generally poor condition chargers. While, other laptops didn't seem to have that issue nearly as often (although breaking the DC jack was a common problem for those folks, but that's a different issue). You shouldn't have to be tender and gentle with the power cable for your device... it should be durable and sta…

Any cable you have to wrap it the way it wants to go, any forcing of flexible wire will always cause damage. That is the nature of wire until we create an improved technology. This is not just computer cords, it is ALL cable, from power supply for concerts to the home depot cords (even the most expensive). You can manufacture to allow prolonged life, but expect a heavy/hard user who wants to not take care of the cable, and expects it just to just last will be the first to fail. If you believe otherwise, the cable business needs your help in creating the technology.

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#244

Post by sdk77 »

seesomesense wrote: post #171

"most of the circuitry is covered by the metal heat sink, held in place by yellow insulating tape." This sounds a bit dodgy to me. Could someone with domain expertise comment on whether this is normal ?

It's normal. Actually the part mentioned that wraps around the power supply is not only a heatsink but also a shield for reducing radiated noise. PSU like this are very noisy and without (a.o.) this shield it may not be possible to get it approbated. The shield has transparent plastic foil beneath it to act as an insulator (barely visible on the first photo, but on the picture with the shield removed it's clearly visible). The usage of yellow tape is perfectly normal.

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#245

Post by emp »

radlad wrote: post #154
jegutman wrote: post #113

Earlier quoted context omitted.

I have a cat. None of my other charging cables are vulnerable except my macbook pro one. I've already lost two! Even if they made it easier to replace just the cable that goes from the adapter to the macbook it would be a big win for me.

My cat destroyed mine just last night. :( He has, admittedly, destroyed some headphone cables already, but $15 + some soldering is nothing compared to $80 for my Macbook charger.

They are quite easy to repair. The outside "shield" is actually one of the wires, so very easy to match the ends as the wires have a completely different make up. I have repaired mine in a few places (no cable can take on a bunny). The main problem is the rubber outside appears to be falling apart, much like the biodegradable plastic bags. No real strain on the areas, it simply split and started peeling away.

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#246

Post by Crito »

Bud wrote: post #122
throwaway420 wrote: post #30

Despite the visual appeal of their products, Apple normally does a very good job with prioritizing function over form except in this case with the charger wire being so fragile and thin. I know I'm not the most careful and delicate person in the world, but the failure rate here is ridiculous compared to other similar products I own. The end of the cable gets frayed every single time. Otherwise, Apple makes ridiculous…

I support around 300 Macs for work. In my extensive experience, the deal here is that people are FAR too rough and careless in winding up those charger cables over and over. Apple HAS implemented strain relief here and done their best to make the points of failure less vulnerable. Here's a tip: Instead of yanking the cable at a 90-degree angle and winding as tightly as possible, let the cable come out of the charger…

> "people are FAR too"

I'll stop you right there, No.

Men should not serve machines. Machines should serve men.

If the machine cannot take the abuse that people typically subject it to, then the design of the machine needs to be revised. Trying to modify human behaviour to suit the unnecessary mechanical limitations of machines is insane.

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#247

Post by TD-Linux »

kens wrote: post #102
yourapostasy wrote: post #84

Earlier quoted context omitted.

Please forgive the ignorant questions of a software guy that probably have blindingly obvious answers to a EE. Does this mean that theoretically, I could attach a 18V/18.5V [0] DC power source (like a solar panel array running into a DC-DC converter) to the prongs and as long as I can supply about 100W/8.5A my MacBook Pro will boot? [0] http://apple.stackexchange.com/questions/111250/how-to-charg...

Chargers require a minimum voltage to work. They typically say 85V and might work with lower, but I expect 18V is way too low. I'd also be very nervous about feeding DC into a PFC circuit (which is designed to track the AC waveform) - does anyone know for sure what PFC does if you feed it the wrong frequency? (Someone else asked about 400Hz aircraft power too.)

It probably won't blow anything up, but the active PFC might not be very happy as it tries to track the AC waveform to control the current draw. It might just not work.

You'd be better off getting one of the cheaper clone adapters with passive or no PFC if you want to make a dedicated DC power supply.

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#248

Post by radoslawc »

grkvlt wrote: post #230
radoslawc wrote: post #214

Earlier quoted context omitted.

Just a vent and kind of warning: I've got cat for 1.5 year, and this confirms my impression that they are horrible animals to be pets. Clawing everything, chewing on expansive stuff, peeing, vomiting, defecating on bed, sofa, chairs. If you're considering having cat, please think twice.

I think you may be a bad cat _owner_ from the sound of it. All those behaviours are signs of an unhappy animal, partiularly urinating and defecating on furniture. Do you perhaps not devote enough time to interacting with your pet? Based on the age of the cat, you are probably through the 'aww, cute' kitten stage, and now have an adult cat, and discovering that, like any relationship, you need to invest in it to make…

I might be, or he's total a-hole. But it's more complicated than this. He's 8, spent one year in shelter since everytime someone entered room he was hiding, so no one took him. He "exercises" daily, got full vet checkup, bloodwork has better than I do (kidney problems might lead to urinating all over the place), I've bought Feliway electric dispenser, checked 6 kinds of kitty litter and testing 7th, he was nutred in shelter. What I meant, this is very variable species when it comes to behavioral "diversity", and people are simply not counting it in when thinking about having cat. Especially that whole internet is (for lack of better word) saturated with cute cat pictures. I know it's just animal, and this particular specimen, very particular, still I had to throw away 2 beds, sofa, chair, mattress, 5 pairs of shoes, some clothes and pillows.

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#249

Post by r00fus »

ghaff wrote: post #216
cptskippy wrote: post #207

Earlier quoted context omitted.

> Apple HAS implemented strain relief Apple favors form over function and tries to make their cables in interfaces as small as possible. The result is that there's no room left in their designs for adequate strain relief. They end up using the smallest cables they can get away with and have a bushing around the cable as it enters it's housing to protect against lateral force and that's about it. There's rarely any in…

The odd thing is that the cable going to the laptop is probably too thin/not stress-relived enough (I've "only" had one fail but it seems a marginal design). However, at the same time, the alternate plug with the extension length of cord attached practically looks and weighs like something I'd attach to a mainframe. I don't travel with it for that reason. It's always seemed to me as if the two different components we…

It doesn't look elegant and it may not be UL tested, but I've used AC cord segments from other laptops [1].

[1] http://www.newegg.com/AC-Power-Cords-for-Laptop/SubCategory/...

Re: Macbook charger teardown: surprising complexity inside Apple's power adapter

#250

Post by ars »

Bud wrote: post #122
throwaway420 wrote: post #30

Despite the visual appeal of their products, Apple normally does a very good job with prioritizing function over form except in this case with the charger wire being so fragile and thin. I know I'm not the most careful and delicate person in the world, but the failure rate here is ridiculous compared to other similar products I own. The end of the cable gets frayed every single time. Otherwise, Apple makes ridiculous…

I support around 300 Macs for work. In my extensive experience, the deal here is that people are FAR too rough and careless in winding up those charger cables over and over. Apple HAS implemented strain relief here and done their best to make the points of failure less vulnerable. Here's a tip: Instead of yanking the cable at a 90-degree angle and winding as tightly as possible, let the cable come out of the charger…

> The simple fact is that there is no way to make a wire that gets twisted and yanked and bent at a 90-degree angle, and which will nevertheless last forever.

If you can, count how many strands are inside that wire. If it's fewer than 90 strands you know why this wire fails.

I bet it's probably only 19 which is the minimum for a moving wire not to break.

> That's just not a thing we can do.

Yes it is. Assembly robots that move all day can have even 5,000 strands in the wires in a careful helical winding pattern that prevents the strands from being under tension - those will not break even after constant movement and folding.

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