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The capacitor that Apple soldered incorrectly at the factory

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Re: The capacitor that Apple soldered incorrectly at the factory

#201

Post by RulerOf »

sillystuff wrote: post #183
Workaccount2 wrote: post #129

Earlier quoted context omitted.

I am assuming you are an ee (like myself)...I have never designed a product with a built in expiration, nor have I ever seen any app notes or write ups on the engineering of it - something engineers love to do. What I have seen done is cheaping out on parts in order to get the price as low as possible, because customers shop primarily on price. Not to lash out, but it kind of hits a nerve for me, because people think…

Not LED light bulbs specifically, but... "The Phoebus cartel engineered a shorter-lived lightbulb and gave birth to planned obsolescence" https://spectrum.ieee.org/the-great-lightbulb-conspiracy

It's true that the Phoebus cartel arranged to have light bulbs die after a certain number of hours, but bulb lifetime is a trade off between lumens, filament life, and energy consumption. The cartel-defined lifetime limit sits very close to the sweet spot for all of those metrics for incandescent bulbs.

Technology Connections explained this well in a video about a year ago: https://youtu.be/zb7Bs98KmnY

Re: The capacitor that Apple soldered incorrectly at the factory

#202

Post by com2kid »

kube-system wrote: post #185
com2kid wrote: post #176

Earlier quoted context omitted.

> If anything, the lifespan of a ~$1.50 household LED bulb is quite incredible. I'm not sure exactly how anyone would be able to increase the lifespan at that price point and keep the traditional Edison form factor. I don't think I've had any last more than 5 years. If you bought a cutting edge LED bulb back in 2002 or so, those had a life expectancy of over 60 years, and the build quality was such that you could rea…

Yeah I would hope those bulbs were built pretty well, they were crazy expensive... expensive enough that they wouldn't be competitive in lifetime-per-dollar against today's crappiest bulbs even if they lasted a person's entire lifetime. > I don't think I've had any last more than 5 years. Do you shut them off every 3 hours? That's probably what the estimate on the box is based on. Run the same bulb half the day and y…

> I've seen them. And dissected my own. Still, at the price that modern LED bulbs are being made, I'm surprised they're built as well as they are. Brand name Sylvania bulbs are $0.79/ea in a bulk Amazon right now.

LED bulbs aren't lasting any longer than incandescent bulbs used to. My house has 2 bathrooms, one had incandescent bulbs when I moved in and I didn't bother to replace them. Those incandescent bulbs have outlived multiple sets of LED bulbs in the other bathroom.

I honestly worry about the increase in e-waste with LED bulbs vs the old incandescent bulbs.

> Do you shut them off every 3 hours? That's probably what the estimate on the box is based on. Run the same bulb half the day and you'll only get 2.5 years out of it.

Which given that LEDs should damn well last 20-30 years of always being on, this is all a farce. I can't even pay 2x the price to buy a bulb with an honestly stated lifetime on it.

> Yeah I would hope those bulbs were built pretty well, they were crazy expensive... expensive enough that they wouldn't be competitive in lifetime-per-dollar against today's crappiest bulbs even if they lasted a person's entire lifetime.

I bet they would be. Given LED bulbs last less than 3 years now, with some not even lasting 2 years, a 20-30 year bulb could cost 4x as much and be competitive.

The real problem is that those long lifetime LED bulbs are not driven as hard, so the light output isn't nearly as high. AFAIK all research in the last 20 years has been into bright LEDs with meh lifetimes, so I wonder if it is even possible to mass produce long lifetime consumer LEDs anymore.

(Except the LEDs in all my consumer electronics have no problems staying on for 5 years non-stop! Tiny output, long lifespan...)

Re: The capacitor that Apple soldered incorrectly at the factory

#203

Post by 65a »

chefandy wrote: post #130

What’s the liquid in the old capacitors? PCBs? (as in polychlorinated biphenyls… that abbreviation collision always annoyed me.) I think I know exactly enough about electronics to ask more annoying questions than someone who doesn’t know anything at all.

Electrolytics are usually nothing too fancy, but it is proprietary. Water and electrolytes, hence the name. PCBs are in the big transformers and what used to be called bathtub caps which looked like this https://i.ebayimg.com/images/g/VjwAAOSwfGJjYtHx/s-l400.jpg (think 1950s electronics stuff)

Re: The capacitor that Apple soldered incorrectly at the factory

#204

Post by phire »

rwmj wrote: post #121
mhardcastle wrote: post #108

Why include that capacitor at all if it doesn't matter whether it works?

If you look at the traces you can see the capacitor is right next to the power connector, on the -5V rail (which is not used for much, only for the RS422 serial port). The capacitor will be there to smooth the power supply when the machine is just switched on, or there's a sudden load which causes the voltage to "dip" above -5V. Basically it's like a tiny rechargable battery which sits fully charged most of the time,…

> It's only needed for rare occasions.

The two RS-422 ports are actually used quite often on these old Macs for printers, modems and apple talk networking. It was the only communication port, as there was no parallel port. They were backwards compatible with RS-232.

So it obviously worked well enough.

The backwards cap was measured to reduce the voltage to about -2.4v.

I suspect that all it did was reduce the maximum range, which started at a massive 1,200 meters for RS-422 (and a good 10m for RS-232)

Re: The capacitor that Apple soldered incorrectly at the factory

#205

Post by Dylan16807 »

kube-system wrote: post #146
magic_smoke_ee wrote: post #142

Earlier quoted context omitted.

I seriously doubt it's ever a deliberate conspiracy in engineering apart from shenanigans like what happened at VW, but it's net effect of product managers, accountants, and contract manufacturers who modify PCBs and BOMs after it's passed off to them to save money on retail products. And so it's likely unintentional with negligence, but it benefits the company. Except for some Samsung appliances made ~ 2010-2014 whi…

> Except for some Samsung appliances made ~ 2010-2014 which seemed to fail just after their warranties expired. And? That just sounds like they have good engineers. If you are designing a machine, you have an target lifetime. You'd obviously want the product to last through the warranty period, because warranty claims are a cost to the company. Every choice of a component affects lifetime. Designers of mass-market pr…

> And? That just sounds like they have good engineers. If you are designing a machine, you have an target lifetime. You'd obviously want the product to last through the warranty period, because warranty claims are a cost to the company.

> Every choice of a component affects lifetime. Designers of mass-market products can't just use premium components everywhere -- the mass market will not pay steep premiums for otherwise equivalent products.

Dying just out of warranty is only okay if the warranty covers the actual expected lifetime of the product. And for appliances, it doesn't.

The difference between a 5 year washing machine and a 30 year washing machine is not very big. Anyone pinching those specific pennies is doing a bad thing.

Re: The capacitor that Apple soldered incorrectly at the factory

#206

Post by Dylan16807 »

kube-system wrote: post #154
magic_smoke_ee wrote: post #150

Earlier quoted context omitted.

You're making a pretty awkward value judgement about what a "good" engineer is, but you're describing an unethical one with a bizword like "value engineering". I realize ethics are no longer understood by much of Western society because the culture teaches transactionality, worships trickle-down economics and greed, and hyperindividualism. > It isn't that. It's pressure at the shelf that does it. Consumers behavior s…

A good engineer is one that has a job, doesn't put their employer out of business, and produces work that fulfills the requirements they're given. Many people think there's some unethical conspiracy going on, and consumers actually want a product that lasts a long time, but companies are refusing to give it to them. But this is projection of individual preferences on to the market as a whole. Consumers want cheap shi…

> If consumers really wanted to pay a premium for high duty-cycle equipment with premium lifespans, they can already do that by buying commercial grade equipment. But they don't.

That costs a ton. I just want a better lifespan, I don't want to 20x the duty cycle and also pay B2B prices.

It's too hard to figure out which consumer products have a better lifespan, so companies do a bad job of catering to that need. This makes companies try too hard to be cheapest, and they often fall below the sweet spot of longevity versus price. Then everyone is worse off. That's not the fault of the engineer but it still means the engineer is participating in making things worse.

Re: The capacitor that Apple soldered incorrectly at the factory

#207

Post by Dylan16807 »

kube-system wrote: post #187
harimau777 wrote: post #181

Earlier quoted context omitted.

A good engineer provides value to society. If they fulfill requirements that are bad for others then they are not good engineers. I seems to me that there is also a social dynamic to things. If consumer grade products become a race to the bottom then it is going to become more difficult for regular people to purchase products which aren't low quality. There's also a degree to which society (e.g. in the form of govern…

The fact that poor people can now afford to own some household appliances isn't a huge value to society? It completely changed the way our societies operate. I think it is a good thing that people have the option to buy crappy washing machines, rather than being forced to use the washboard and bucket my grandmother used. Yeah, they sometimes do develop a bad belt, or the timer mechanism might fail. But it beats being…

> If anything, squeezing a few more pennies out of that BOM is going to lift some people at the fringes out of poverty.

If it squeezes a small but solid chunk out of product lifetime too, then it's also likely to harm people on the fringes. If they can buy it with one less month of savings, but then it breaks a couple months earlier, they're probably worse off. (For actual pennies divide both of those numbers by some orders of magnitude.)

Re: The capacitor that Apple soldered incorrectly at the factory

#208

Post by robertlagrant »

belval wrote: post #135
Workaccount2 wrote: post #129

Earlier quoted context omitted.

I am assuming you are an ee (like myself)...I have never designed a product with a built in expiration, nor have I ever seen any app notes or write ups on the engineering of it - something engineers love to do. What I have seen done is cheaping out on parts in order to get the price as low as possible, because customers shop primarily on price. Not to lash out, but it kind of hits a nerve for me, because people think…

To be fair this is hardly limited to EE and is the issue with the race to the bottom in all product categories. Make long-lasting high-quality 100$ pants? People prefer spending 10$ on Shein. Additionally, the issue is that as a consumer, it's not easy to differentiate between quality markup and greedy markup. I don't see the cap manufacturer on the box so the 25$ light bulb might last 10 years or it might last 6 mon…

> Make long-lasting high-quality 100$ pants? People prefer spending 10$ on Shein.

This is just fashion, right? As something becomes commoditised, it starts to become subject to fashion, which means cheap and looks fashionable is more important than durability. So you can buy one every year and keep up, and throw away the old one.

Re: The capacitor that Apple soldered incorrectly at the factory

#209

Post by robertlagrant »

magic_smoke_ee wrote: post #150
kube-system wrote: post #146

Earlier quoted context omitted.

> Except for some Samsung appliances made ~ 2010-2014 which seemed to fail just after their warranties expired. And? That just sounds like they have good engineers. If you are designing a machine, you have an target lifetime. You'd obviously want the product to last through the warranty period, because warranty claims are a cost to the company. Every choice of a component affects lifetime. Designers of mass-market pr…

You're making a pretty awkward value judgement about what a "good" engineer is, but you're describing an unethical one with a bizword like "value engineering". I realize ethics are no longer understood by much of Western society because the culture teaches transactionality, worships trickle-down economics and greed, and hyperindividualism. > It isn't that. It's pressure at the shelf that does it. Consumers behavior s…

> I realize ethics are no longer understood by much of Western society because the culture teaches transactionality, worships trickle-down economics and greed, and hyperindividualism.

You realise incorrectly, I would say. It's very defensible to claim that Western society has the most - by a giant margin - social, economic and technological advances in history, and to boil it down to this is just a bit silly, in my opinion.

Re: The capacitor that Apple soldered incorrectly at the factory

#210

Post by weinzierl »

"The capacitor might not have been doing its job properly if it was installed backwards, but it didn’t seem to really be hurting anything."

This is the buried lede! I am of the opinion that half of the capacitors in any modern circuit are useless; the trouble is we don't know which half.

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