[HN Gopher] The capacitor that Apple soldered incorrectly at the...
___________________________________________________________________
The capacitor that Apple soldered incorrectly at the factory
Author : zdw
Score : 436 points
Date : 2024-11-27 05:10 UTC (17 hours ago)
(HTM) web link (www.downtowndougbrown.com)
(TXT) w3m dump (www.downtowndougbrown.com)
| shiroiushi wrote:
| Apple should be required to do a recall for these motherboards.
| wetpaws wrote:
| For 1993 hardware?
| toast0 wrote:
| If they do a recall, it will say they should be discarded. Sony
| has a recall on all its trinitron tvs made before the end of
| 1990 like this:
|
| https://www.sony.jp/products/overseas/contents/support/infor...
| shiroiushi wrote:
| This shouldn't be allowed at all: if the product was bad all
| along, they should be required to fix it, and shouldn't be
| able to say "well, it's old, so you should just trash it",
| which means they don't suffer any penalty whatsoever.
| duskwuff wrote:
| I don't think that's a reasonable expectation in general,
| and certainly not in this case. The affected TVs were all
| _at least_ 20 years old - that 's well beyond the expected
| useful lifespan of even a modern TV, let alone an older
| model like these. Nor is it clear what Sony could
| reasonably have done to repair them; even by 2010, a lot of
| the parts used in CRT TVs were out of production and
| unavailable.
| shiroiushi wrote:
| Maybe you're too young to remember, but people used to
| keep TVs for much longer periods before HDTV and flat
| panels came out.
|
| Also, these TVs are apparently fire hazards. It doesn't
| matter that they're 20 years old (at the point of the
| "recall" in 2010).
|
| I doubt the parts necessary to fix them were out of
| production; you can get parts for truly ancient
| electronics still. Things like capacitors don't become
| obsolete. The recall doesn't specify exactly which
| component is problematic, but says it's age-related,
| which usually points to capacitors.
| tobr wrote:
| This. I've known a TV that was in more or less daily use
| for over 30 years. Not sure why we stopped expecting that
| from electronics.
| eru wrote:
| Because electronics got so much better so much faster,
| that the vast majority of customers did not want to use
| old hardware.
|
| Especially if customers allowing shorter lifetimes
| allowed companies to lower the prices.
| AnthonyMouse wrote:
| There are many use cases for which a decade-old computer
| is still perfectly serviceable and even where they
| aren't, those computers can be repurposed for the ones
| that are.
|
| Moreover, we're talking about televisions and old Macs.
| TVs with higher resolutions might come out, but lower
| resolution ones continue to be sold new (implying demand
| exists at some price), and then why should anybody want
| to replace a functioning old TV with a newer one of the
| same resolution?
|
| Much older computers continue to be used because they run
| software that newer computers can't without emulation
| (which often introduces bugs) or have older physical
| interfaces compatible with other and often extremely
| expensive older hardware.
|
| If people actually wanted to replace their hardware
| instead of fixing it then they'd not be complaining about
| the inability to fix it.
| shiroiushi wrote:
| >There are many use cases for which a decade-old computer
| is still perfectly serviceable and even where they
| aren't, those computers can be repurposed for the ones
| that are.
|
| It depends. Older computers usually guzzle power,
| especially if you look at the absolutely awful Pentium4
| systems. You're probably better off getting a RasPi or
| something, depending on what exactly you're trying to do.
| Newer systems have gotten much better with energy
| efficiency, so they'll pay for themselves quickly through
| lower electricity bills.
|
| >TVs with higher resolutions might come out, but lower
| resolution ones continue to be sold new (implying demand
| exists at some price)
|
| We're already seeing a limit here. 8k TVs are here now,
| but not very popular. There's almost no media in that
| resolution, and people can't tell the difference from 4k.
|
| For a while, this wasn't the case: people were upgrading
| from 480 to 720 to 1080 and now to 4k.
|
| >and then why should anybody want to replace a
| functioning old TV with a newer one of the same
| resolution?
|
| They probably don't; if they're upgrading, they're
| getting a higher resolution (lots of 1080 screens still
| out there), or they're getting a bigger screen. It's
| possible they might want newer smart TV features too:
| older sets probably have support dropped and don't
| support the latest streaming services, though usually you
| can just get an add-on device that plugs into the HDMI
| port so this is probably less of a factor.
| ahoka wrote:
| A decade old CPU would be a Haswell, not a Pentium 4.
| aero_code wrote:
| > Older computers usually guzzle power, especially if you
| look at the absolutely awful Pentium4 systems.
|
| https://en.wikipedia.org/wiki/List_of_Intel_Pentium_4_pro
| ces...
|
| The Northwood chips were 50 to 70 W. HT chips and later
| Prescott chips were more 80 to 90 W. Even the highest
| chips I see on the page are only 115 W.
|
| But modern chips can use way more power than Pentium 4
| chips:
|
| https://en.wikipedia.org/wiki/Raptor_Lake
|
| The i5-14600K has a base TDP of 125 W and turbo TDP of
| 181 W, and the high-end i9-14900KS is 150 W base/253 W
| turbo. For example, when encoding video, the mid-range
| 14600K pulls 146 W:
| https://www.tomshardware.com/news/intel-
| core-i9-14900k-cpu-r...
|
| More recent processors can do more with the same power
| than older processors, but I think for the most part that
| doesn't matter. Most people don't keep their processor at
| 100% usage a lot anyway.
| AnthonyMouse wrote:
| > Older computers usually guzzle power, especially if you
| look at the absolutely awful Pentium4 systems.
|
| Even many Pentium 4-based systems would idle around 30
| watts and peak at a little over 100, which is on par with
| a lot of modern desktops, and there were lower and higher
| power systems both then and now. The top end Pentium 4
| had a TDP of 115W vs. 170W for the current top end Ryzen
| 9000 and even worse for current Intel. Midrange then and
| now was ~65W. Also, the Pentium 4 is _twenty two_ years
| old.
|
| And the Pentium 4 in particular was an atypically
| inefficient CPU. The contemporaneous Pentium M was so
| much better that Intel soon after dumped the P4 in favor
| of a desktop CPU based on that (Core 2 Duo).
|
| Moreover, you're not going to be worried about electric
| bills for older phones or tablets with <5W CPUs, so why
| do those go out of support so fast? Plenty of people
| whose most demanding mobile workload is GPS navigation,
| which has been available since before the turn of the
| century and widely available for nearly two decades.
|
| > For a while, this wasn't the case: people were
| upgrading from 480 to 720 to 1080 and now to 4k.
|
| Some people. Plenty of others who don't even care about
| 4k, and then why would they want to needlessly replace
| their existing TV?
|
| > They probably don't; if they're upgrading, they're
| getting a higher resolution (lots of 1080 screens still
| out there), or they're getting a bigger screen.
|
| That's the point. 1080p TVs and even some 720p TVs are
| still sold new, so anyone buying one isn't upgrading and
| has no real reason to want to replace their existing
| device unless it e.g. has a design flaw that causes it to
| catch fire. In which case they should do a proper recall.
| shiroiushi wrote:
| >Not sure why we stopped expecting that from electronics.
|
| For TVs specifically, the technology changed a lot. For a
| long time, everyone was stuck on the NTSC standard, which
| didn't change much. At first, everyone had B&W TVs, so
| once you had one, there was no reason to change. Then
| color TV came out, so suddenly people wanted those. After
| that, again no reason to change for a long time. Later,
| they got remote controls, so sometimes people would want
| one of those, or maybe a bigger screen, but generally a
| working color TV was good enough. Because TVs were glass
| CRTs, bigger screens cost a lot more than smaller ones,
| and there wasn't much change in cost here for a long
| time.
|
| Then HDTV came out and now people wanted those, first in
| 720p, and later in 1080i/p. And flat screens came too, so
| people wanted those too. So in a relatively short amount
| of time, people went from old-style NTSC CRTs to seeing
| rapid improvements in resolution (480p->720p->1080->4k),
| screen size (going from ~20" to 3x", 4x", 5x", 6x", now
| up to 85"), and also display/color quality (LCD, plasma,
| QLED, OLED), so there were valid reasons to upgrade. The
| media quality (I hate the word "content") changed too,
| with programs being shot in HD, and lately 4k/HDR, so the
| difference was quite noticeable to viewers.
|
| Before long, the improvements are going to slow or stop.
| They already have 8k screens, but no one buys them
| because there's no media for them and they can't really
| see the difference from 4k. Even 1080p media looks great
| on a 4k screen with upscaling, and not that much
| different from 4k. The human eye is only capable of so
| much, so we're seeing diminishing returns.
|
| So I predict that this rapid upgrade cycle might be
| slowing, and probably stopping before long with the
| coming economic crash and Great Depression of 2025. The
| main driver of new TV sales will be people's old TVs
| dying from component failure.
| bregma wrote:
| > The human eye is only capable of so much, so we're
| seeing diminishing returns.
|
| Or not seeing diminishing returns. Which is the point.
| Someone wrote:
| > At first, everyone had B&W TVs, so once you had one,
| there was no reason to change
|
| Televisions improved over time:
|
| - screens got flatter
|
| - screens got larger
|
| - image quality improved
|
| - image contrast increased (people used to close their
| curtains to watch tv)
|
| - televisions got preset channels
| kstrauser wrote:
| Great points. The TV I have today is approaching my
| platonic ideal screen. It's as big as it can get without
| having to continually look around to see the whole
| screen. Sit in the first row of a movie theater to
| understand how that can be a bad thing. The pixels are
| smaller than I can see, it has great dynamic range, and
| the colors can be as saturated as I'd ever want. There's
| not much that can be improved on it as a traditional
| flatscreen video monitor.
| blitzar wrote:
| > Not sure why we stopped expecting that from
| electronics.
|
| Last years model only does 4k, my eyes need 8k
| xattt wrote:
| 32K ought to be enough for anybody.
| blitzar wrote:
| 32K is going to look so lifeless and dull after you try
| 64k.
| xattt wrote:
| When will the pixels start to approach erythrocyte-level
| density like on the Vision Pro?
|
| edit: Anywhere between 208K to 277K.
| bloak wrote:
| My experience of ancient CRT devices is that the display
| gets gradually dimmer. I once had a TV that was only
| really usable after dark -- but that's the only time I
| wanted to use it anyway -- and a huge Sun monitor that
| was only just about readable in total darkness, but we
| kept it because we also had a Sun server that we didn't
| know how to connect to any other monitor and we were
| worried that one day we wouldn't be able to SSH to it,
| but in fact the server never once failed.
| robocat wrote:
| > daily use for over 30 years
|
| However that doesn't imply TVs were that reliable.
|
| Before the 90s TV repairman was a regular job, and TVs
| often needed occasional expensive servicing. I remember a
| local TV repair place in the 90s which serviced "old"
| TVs.
| nuancebydefault wrote:
| Suppose they would recall all the old tv's with known
| faults, can those be fixed to become conform to (today's)
| quality and safety standards, while being full of old
| components with characteristics beyond original
| tolerances?
| kbelder wrote:
| > that's well beyond the expected useful lifespan of even
| a modern TV, let alone an older model like these
|
| A modern TV may have an expected lifespan of five years.
| TVs from several decades ago had lifespans of... several
| decades. Quality has plummeted in that market.
| eru wrote:
| Only one metric of 'quality' has plummeted.
|
| A rock lasts billions of years, but its quality as a TV
| is rather questionable.
| azinman2 wrote:
| 5 years? Is that really true? I'm currently using an LG
| from 2017 and cannot imagine needing to change it. I
| would be shocked if it stopped working.
| tverbeure wrote:
| I don't think it is true at all.
|
| There's nothing inside today's monitors or TVs that can't
| run for at least 10 years. Our main TV, 42" 720p LCD, is
| from 2008, and I have monitors that are just as old.
| Supernaut wrote:
| Yep. My TV, a 42" Panasonic plasma, dates from 2009 and
| is still working perfectly. I haven't replaced it,
| because why would I?
| rvense wrote:
| But when it does, it will probably be the capacitors in
| the power supply that have dried out.
| verzali wrote:
| Is that really the case? Because if so, it seems like
| simply replacing the capacitors would save a lot of waste
| and unnecessary purchases of new TVs...
| rvense wrote:
| This is a very common fault, yes. Power supply issues in
| general. It is also not uncommon for people to replace
| e.g. Wifi routers because the wall warts fail.
|
| It comes down to a few people don't knowing a lot about
| it - and I'm not blaming anyone for that, we all have our
| interests and most people have more than enough to do
| already to worry about what goes on inside their stuff.
|
| Also, electronics are, to a lot of people in a lot of
| places, so cheap that they would rather just curse a
| little and buy a new thing, instead of bothering with
| taking the thing to a shop. And of course a few hours of
| skilled labour in a big city in the west might also be
| almost as expensive as making a whole new TV in a factory
| in Asia plus shipping, so it might not even make economic
| sense.
| quesera wrote:
| > _And of course a few hours of skilled labour in a big
| city ..._
|
| In many/most places, these repair shops don't even exist
| any more, because the products have gotten too
| complicated/integrated/parts-unavailable, and the
| economics are nonsensical.
| xxs wrote:
| Electrolytic capacitors are not solid state and likely #1
| failure mode for most electronics. There are options for
| better (e.g. Al polymer) capacitors that are rather
| expensive - overall good capacitors are 'expensive', e.g.
| more than a dollar a piece in some cases.
|
| The 2nd most common failure mode gotta be the mlcc (multi
| layer ceramic capacitor) cracks/shorts.
| nuancebydefault wrote:
| How can I even know which capacitor is faulty?
| xxs wrote:
| That would require some experience, yet the most common
| visual clue would be 'bulging'. There are some ways to
| measure ESR w/o desoldering but they won't be reliable at
| all times.
|
| Measuring voltages, peak to peak, is a bit more work.
| toast0 wrote:
| If your model was popular, there's likely a recap kit for
| its power supply. It usually makes senss to swap all the
| capacitors in the kit, unless the kit instructions say
| otherwise.
|
| You can look for physical signs of degredation (bulgy,
| leaky, discolored), but to really test a capacitor for
| capacititance, you need to take it out of the circuit, at
| which point, you may as well put a new, high quality
| capacitor in.
|
| The OEM capacitors may likely have a just right voltage
| rating, a new one with a higher voltage rating (and same
| capacitance, compatible type) may last longer in cirucit
| as well.
| xxs wrote:
| > new one with a higher voltage rating (and same
| capacitance, compatible type) may last longer in cirucit
| as well.
|
| That's not necessarily true, higher voltage rating equals
| higher ESR which means more heat.
| alias_neo wrote:
| I have an LG OLED from 2017. It started getting really
| bad screen burn/pixel degredation just after the 6 year
| mark (6 year warranty), I did a quick search on Youtube,
| and lo-and-behold, a whole bunch of other people, with
| the same model, started having the same screen burn-in
| issues at the same age!
|
| It covers the middle third of the screen, top to bottom,
| and the entire bottom 1/4 of the screen with some odd
| spots as well, it's really distracting and essentially
| makes the TV useless (to me).
| cmgbhm wrote:
| I have an LG about that vintage and it's starting to
| black out when doing 4K content. All components before it
| switched out and up to date in firmware. Reatarting
| works, sometimes all day, sometimes 1 minute.
|
| My other TV about the same vintage is starting to have
| stuck pixels in the corner.
|
| Modern failure modes aren't nearly as graceful.
| Peanuts99 wrote:
| A TV used to cost a few weeks pay and now you can get a
| TV for the equivalent of a few hours pay. There just
| isn't much of a market for a $3000+ TV.
| xxs wrote:
| Few usually means 3-5 or so, a half decent TV would be at
| least half a grand. That's rather high hourly pay rate.
| toast0 wrote:
| Explain to me why this tv for $100 [1] isn't perfectly
| suitable to replace a 2008 40" 1080p Samsung LCD with
| florescent backlight that 2was a deal at $1000. Yeah, you
| could get something bigger and better. Yes, price
| comparison on a sale week is a bit unfair.
|
| [1] https://www.bestbuy.com/site/tcl-40-class-s3-s-class-
| 1080p-f...
| xxs wrote:
| FYI: bestbuy is unavailable outside the US (the site I
| mean), or likely NA.
| bee_rider wrote:
| It is a legitimate business decision, to sell things that
| last less than 20 years. Fine, I think it is lame, but it
| is their choice.
|
| But, we shouldn't let companies get away with selling
| products that catch fire after working fine for 20 years.
| InsideOutSanta wrote:
| "that's well beyond the expected useful lifespan of even
| a modern TV, let alone an older model like these"
|
| People still run these Trinitron TVs to this day.
| PittleyDunkin wrote:
| > that's well beyond the expected useful lifespan of even
| a modern TV
|
| What? That's nuts. Why bother buying a tv if you're
| immediately going to throw it in the trash
| tengbretson wrote:
| My radial arm saw ended up getting a product recall for
| simply being too difficult for the average consumer to use
| safely. The "recall" amounted to them sending you
| instructions to cut off a critical power cord and mail it
| in to them, and they send you a $50 check.
| bigstrat2003 wrote:
| That is completely unreasonable. Companies can't be
| expected to take in and repair devices that old.
| Throw8394045 wrote:
| They don't do recalls even on modern hardware. But soldering
| hacks are no longer possible, all parts are serialized.
|
| Louis Rossmann made many videos on this.
| shiroiushi wrote:
| What are you talking about? Capacitor technology hasn't
| changed substantially in decades, and it's just as possible
| to change caps with a soldering iron now as it was 20 years
| ago. I have no idea what you mean by "serialized".
| fragmede wrote:
| not capacitors, but more advanced components, like the
| camera, have serial numbers embedded in them, and the
| serial number needs to match, otherwise it won't accept the
| component. Components off a stolen device are put on a list
| and won't work in admirer another phone, so stolen phones
| aren't even worth anything for parts, driving down the
| market for stolen phones. It also makes the job of repair
| shops harder, which is collateral damage in Apple's eyes,
| but is very much material for anyone running a repair shop.
| shiroiushi wrote:
| I see. Yes, that is a big problem for component swapping.
| I was just thinking of electronics with old/faulty caps;
| those will still be repairable.
| pkolaczk wrote:
| Doesn't Apple offer a way to re-pair components if they
| are genuine and not stolen (unregistered from the
| previous AppleId)?
| fragmede wrote:
| and Apple will very happily charge you for that privilege
| jajko wrote:
| TBH for such a critical piece of our modern lives, I
| would be more than fine to pay extra to be 100% sure I am
| getting original parts, put in professionally and in
| secure manner re my personal data. I wish ie Samsung had
| such service where I live.
|
| We anyway talk about expensive premium phones to start
| with, so relatively expensive after-warranty service is
| not shocking.
|
| This may actually eventually sway me into apple camp.
| This and what seems like much better theft
| discouragement.
| raxxorraxor wrote:
| I don't. Such mechanisms also disqualify 3rd party
| replacements. It is just a wasteful solution. Not that
| any smartphone would qualify as decent here.
|
| But as a customer it will overall be more expensive for
| you.
| jajko wrote:
| There are things in life where amount paid is far from
| top priority, and phone is one these days. With sums we
| talk about, I just don't care anymore, and Samsung I have
| now is even more expensive and more wasteful.
|
| Re wastefulness - a decent laptop causes 10x more
| pollution to manufacture than phone. Desktop PC 10x that.
| TVs. Cars. Clothing. Phones are very much down a very
| long line of higher priority targets for eco friendly
| approach.
| ethernot wrote:
| The only reason this is an issue for repair shops is they
| can't sell you recycled stolen parts at bottom of market
| prices for a sky high mark up. On top of that the "non
| genuine parts", some of which really are utterly dire,
| show up in the OS as being not genuine parts. Buying
| genuine parts, which are available from Apple, eats into
| the margins. There is very little honour in the repair
| market, despite the makeup applied to it by a couple of
| prominent youtubers and organisations.
|
| The amount of horror stories I've seen over the years
| from independent repairers is just terrible. Just last
| year a friend had a screen hot snotted back on their
| Galaxy.
| liontwist wrote:
| > they can't sell you recycled stolen parts at bottom of
| market prices for a sky high mark up
|
| What represents a more efficient economy. The one where
| broken phones get reused for parts or the one where you
| have to throw them away?
| ethernot wrote:
| The economy that isn't backed with criminal activity and
| loss for customers.
| moooo99 wrote:
| > The only reason this is an issue for repair shops is
| they can't sell you recycled stolen parts at bottom of
| market prices for a sky high mark up.
|
| This is just incredibly dishonest framing and completely
| ignoring what the right to repair and third party repair
| shop issue is all about.
|
| > Buying genuine parts, which are available from Apple,
|
| It is not a margin problem, it is an availability
| problem. Apple does not allow third party repair shops to
| stock common parts, such as batteries or displays for
| popular iPhones. This is only possible when providing the
| devices serial numbers. This effectively prevents third
| party repair shops from competing with Apple or Apple
| authorized service providers because they have
| artificially inflated lead times.
|
| Becoming Apple authorized isn't an option for actual
| repair shops because that would effectively disallow them
| from doing actual repairs when possible, rather than
| playing Dr. Part Swap. Everything what Apple does in the
| repair space essentially boils down to them doing
| everything they can to avoid having competition in the
| repair space.
|
| > eats into the margins
|
| Replacing a 45ct voltage regulator on a mainboard is
| cheaper than replacing the entire mainboard with
| everything soldered on is cheaper, but doesn't allow for
| very nice margins.
|
| > There is very little honour in the repair market
|
| There is very little honour in any market. Honour does
| not get rewarded nowadays, people are in <insert market>
| to make money, if you're lucky they still take a little
| pride in their work. If a repair shop offers good service
| or not should be up to the consumer to determine, not up
| to Apple (or any electriconics manufacturer that employs
| the same tactics).
|
| > makeup applied to it by a couple of prominent youtubers
| and organisations.
|
| That is called marketing, that's what Apple does also
| pretty good. They're also lying when they say they are
| environmentally conscious while they also have their
| genius bar employees recommend an entirely new screen
| assembly on a MacBook just because a backlight cable came
| loose.
|
| > The amount of horror stories I've seen over the years
| from independent repairers is just terrible. J
|
| The amount of horror stories I have experienced with
| Apple is no joke either. Apple is always taking the
| sledgehammer approach with their repairs. I've had the
| pleasure myself to deal with Apple repairs once for my
| old 2019 MBP. It wouldn't take a charge anymore, went to
| the Genius Bar and received a quote for a new mainboard
| costing well over 1000 EUR. Being familiar with some of
| the more technical videos of Rossmann etc, I found one
| electronics repair store that actually does board level
| stuff and got it fixed for a fraction of the price (iirc
| it was ~200 EUR).
| cosmic_cheese wrote:
| Even if Apple has room for improvement here, I think it's
| still worth it to try to curb the market for stolen
| parts, because that's going to exist even if Apple sold
| spare parts in bulk at-cost simply because there exist
| unscrupulous repair shops that have no qualms with
| charging you OEM part prices while using gray market
| parts that cost a fraction as much on eBay, Aliexpress,
| etc.
|
| For instance, maybe Apple could supply parts in bulk to
| repair shops but require registration of those parts
| prior to usage. The repaired iPhone would function
| regardless but loudly alert the user that unregistered
| parts were used to repair it. Gray market parts naturally
| aren't going to be able to be registered (either due to
| serial not existing in their system or having been parted
| out from stolen devices), and thus the user is given some
| level of assurance that they're not paid for questionable
| repair services.
| bigstrat2003 wrote:
| If you think Apple's part pairing policy has anything to
| do with consumer benefit, I have a bridge in Arizona to
| sell you.
| raxxorraxor wrote:
| It is not about stolen phones, it is about monetization
| of customer services. If stealing phones was legal, job
| description for procurement/purchase departments would
| look differently as well.
| codewiz wrote:
| Commodore had _3_ capacitors mounted backwards on the A3640, the
| CPU board of the Amiga 4000 with 68040 processors:
| https://youtu.be/zhUpcBpJUzg?si=j6UFmIJzoC-UDS6u&t=945
|
| Also mentioned here: https://amiga.resource.cx/exp/a3640
| bogantech wrote:
| Classic Commodore Quality :P
|
| They also had backwards caps on the CD32 and A4000
| krige wrote:
| Commodore just kept doing this. Just listing shoddy
| craftsmanship would take forever, and then we get to
| intentional bad decisions, like giving the A1200 a power supply
| that's both defective (capacitors ofc) and barely enough to
| support the basic configuration with no expansions, which is
| extra funny because PSUs used with weaker models (A500) had
| greater output...
| bbarnett wrote:
| The number of used a500 power supplies I sold to customers
| when I upgraded their a1200 with a GVP 030 board + RAM...
| kstrauser wrote:
| This was the hardware patch I had to install to use a
| CyberstormPPC:
| https://powerup.amigaworld.de/index.php?lang=en&page=29
| rwmj wrote:
| ZX Spectrum +2 shipped with _transistors_ backwards:
| https://www.bitwrangler.uk/2022/07/23/zx-spectrum-2-video-fi...
| This even caused visible artifacts on the display, which was
| apparently not enough for the problem to be noticed at the
| factory.
| extraduder_ire wrote:
| I think Clive Sinclair was notorious for wanting products to
| be brought to market quickly, with pretty aggressive feature
| sets. They very well may have noticed it at the factory, but
| didn't want to do a fix because it was technically
| functional.
| ethbr1 wrote:
| Well, today I learned to install one capacitor in reverse
| orientation on the PCB on a 34 year old computer...
|
| Definitely starting Wednesday off productively.
| xeyownt wrote:
| At least you made my Wednesday ;-)
| phire wrote:
| I actually have an LC III in storage, so I might actually be
| able to make use of this article.
|
| I think this will allow me to classify today as productive.
| InsideOutSanta wrote:
| Yeah, I have a Performa 450, which I believe is the exact
| same computer sold under a different name. So this is
| definitely important to know. I can go back to bed now, my
| job for today is done.
| grujicd wrote:
| Well, until today I didn't even know capacitor can have
| orientation! So more productive Wednesday than yours. In entry
| level electronics class I had decades ago it was always treated
| as a component that works the same way no matter in which
| direction the current flows.
| fredoralive wrote:
| There are polarised and unpolarised capacitors. Stuff like
| basic decoupling capacitors tend to be unpolarised.
| Filligree wrote:
| Ceramic capacitors don't have polarity. Electrolytic ones do.
| Thing is, electrolytic capacitors have far higher capacitance
| for their size -- though also higher resistance.
|
| It's something to check, but the polar ones should be clearly
| marked as such.
| magic_smoke_ee wrote:
| Electrolytic capacitors are kinda like lead-acid batteries
| in that they are polarized through manufacturing processes.
| A voltage is applied in the factory to anodize the anode
| with a thin oxide layer. For fun, I think it would be
| possible to buy a quality low voltage cap and reverse the
| polarity of it in-situ which would remove the anodization
| from the new cathode and deposit a new layer on the new
| anode (former cathode) hopefully without over-pressurizing
| it to bursting, albeit with much less anticipated lifespan.
|
| PSA: Electrolytic capacitors have a rough lifespan of 10
| years. Any much older than that need to be checked out-of-
| circuit for ESR and then capacitance. Also, tantalums
| (historically) suck(ed). [0] Quality audio equipment from
| the 80's like a/d/s/ car amps used only ceramic caps and
| other over-engineered passives, and have the potential (pun
| intended) to basically last forever.
|
| 0. https://www.eevblog.com/forum/projects/whenwhy-(not)-to-
| use-...
| kevindamm wrote:
| Or much shorter, around two years, if it was part of the
| Capacitor Plague.
|
| https://en.wikipedia.org/wiki/Capacitor_plague#Premature_
| fai... The normal lifespan of a non-
| solid electrolytic capacitor of consumer quality,
| typically rated at 2000 h/85 degC and operating at 40
| degC, is roughly 6 years. It can be more than 10 years
| for a 1000 h/105 degC capacitor operating at 40 degC.
| Electrolytic capacitors that operate at a lower
| temperature can have a considerably longer lifespan. ...
| The life of an electrolytic capacitor with defective
| electrolyte can be as little as two years.
| Workaccount2 wrote:
| This is also why so many LED bulbs are shit, lots of heat
| in a small space full of electrolytic caps.
| magic_smoke_ee wrote:
| Intentional planned consumption/obsolescence by design.
| This class of problem is where under-regulation and lack
| of standards benefits only sellers and cheats buyers. PS:
| Also, Amazon should be required to test all of the
| electronic, safety, and food products on its site such
| that they can prove safety and standards conformance.
| Filligree wrote:
| That, and customers insisting on preexisting form
| factors. Fitting the electronics _and LEDs_ into the
| space of a traditional lightbulb comes with compromises,
| such as not having proper heat dissipation on either.
| BlueTemplar wrote:
| Yeah, you would think they would be two separate devices
| by now...
| Workaccount2 wrote:
| 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 we design products to purposely
| fail. Hell no, we try really hard to do the opposite, but
| everyone just loves to buy the cheapest shit.
|
| The $25 LED bulb that will last for eternity will rot on
| the shelf next to the $3 bulb that will probably be dead
| in 6 months. And one more "they build these things to
| fail" complaint will be posted online.
| belval wrote:
| To be fair this is hardly limited to EE and is the issue
| with the race to the bottom in all product categories.
| Make long-lasting high-quality 100$ 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
| months just like the 3$ one. At least with the 3$ one I
| can come back and buy another...
| magic_smoke_ee wrote:
| 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 which seemed to fail just after their
| warranties expired. I suspect highly-optimized designs
| for "consumables" like incandescent lightbulbs and parts
| for cars use data to tweak design life, more often than
| not, in their favor. And, with the pressures of
| multinational oligopolies and BlackRock/Vanguard/State
| Street.. there is little incentive to invest $100M into a
| moderately-superior incandescent lightbulb using
| yesterday's technology that lasts 100kh and 5k cycles and
| sells for $1 more than the next one. Maybe if we (perhaps
| a science/engineering nonprofit thinktank that spanned
| the world and gave away designs and manufacturing
| expertise) had quasi-communism for R&D, we could have
| very nice things.
|
| It's not my fault if other people are too dumb to
| comprehend TCO because I would buy the $25 bulb if it had
| a 30 year warranty.
| kube-system wrote:
| > 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 products can't just use premium components
| everywhere -- the mass market will not pay steep premiums
| for otherwise equivalent products.
|
| Value engineering and planned obsolescence are not the
| same thing, but they are often confused.
|
| That being said, Samsung appliances suck and I hate them.
| Mine failed within warranty several times.
|
| > And, with the pressures of multinational oligopolies
| and BlackRock/Vanguard/State Street.. there is little
| incentive to invest $100M into a moderately-superior
| incandescent lightbulb using yesterday's technology that
| lasts 100kh and 5k cycles and sells for $1 more than the
| next one.
|
| It isn't that. It's pressure _at the shelf_ that does it.
| Consumers behavior simply does not reward equivalent-
| feature products with premium components that claim (true
| or not) to have a longer lifespan. Unfortunately, they
| _will_ buy based on their uninformed sense of quality
| first.
|
| If you release a light bulb that is identical to the best
| selling one on the shelf, but claims 10x lifespan, your
| competitor will do something like gluing a weight in
| theirs, putting some marketing BS on the box, and will
| put you out of business. Consumers just don't pick
| products based on _actual_ quality.
| magic_smoke_ee wrote:
| 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 simply does not reward equivalent-
| feature products with premium components that claim (true
| or not) to have a longer lifespan. Unfortunately, they
| will buy based on their uninformed sense of quality
| first.
|
| This is a failure of marketing and buzz of the sales
| channel(s) and manufacturers to educate properly, not the
| failure of the customer.
| kube-system wrote:
| 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 shit
| that is in fashion, and their buying preferences prove
| this time and again. Maybe _you want_ a 50 year old
| toaster in your kitchen, other people are buying products
| based on other factors.
|
| 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.
|
| If you are familiar with the history of home appliances,
| you'd probably come to appreciate the phrase 'value
| engineering'. Even poor people can afford basic electric
| appliances now because of the ingenuous ways that
| engineers have designed surprisingly usable appliances
| out of very minimal and efficient designs.
|
| If you look at ads for electric toasters 100 years ago,
| you'd see they cost over $300 in today's money adjusted
| for inflation. Thank god for value engineering.
| owenversteeg wrote:
| I agree with what you said - engineers do the best they
| can with the budget but the budget is small because
| people won't pay for things that last - but it's worth
| saying that any boards with electrolytic capacitors have
| an inherent built in expiration. Any product with rubber
| has an expiration. Any product with permanent batteries,
| glued or sealed assemblies, or no spare parts. Much of
| that is with the customer's budget, sure. But these days,
| even among expensive things, nearly nothing is built to
| last.
| andrewflnr wrote:
| Please think for a moment not only about whether it's
| feasible for AMZN to run a safety testing program for all
| possible consumer products of our modern technological
| civilization, but whether you really want them to be in
| charge of it. Maybe they should just require
| certifications of testing in the jurisdictions where
| those products are sold?
| gopher_space wrote:
| Isn't faking certs already a problem?
| andrewflnr wrote:
| Probably. Is it a worse problem than Amazon inspecting
| themselves would be? Is it a worse problem than Amazon
| demonstrably already has with policing counterfeits? I'm
| just saying, you could hardly ask for a less-qualified
| authority for product testing. At least with independent
| certs it's vaguely possible to align the incentives
| correctly. With Amazon the incentives would be hosed from
| the start.
| kube-system wrote:
| > Intentional planned consumption/obsolescence
|
| No it isn't. It is simply optimization of price and the
| features/form-factor that many buyers have demanded.
|
| 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.
|
| > Amazon should be required to test all [..] products on
| its site such that they can prove safety and standards
| conformance.
|
| No, the manufacturers should be required to... the same
| way it works for literally every other product with
| safety regulations.
| com2kid wrote:
| > 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 reasonably expect
| to get that.
|
| There are plenty of teardowns on YT showing how poorly
| even major brand name LED bulbs are put together.
| JJMcJ wrote:
| Recently read that if you are going to be using an LED
| bulb in an enclosed space, buy bulbs designed for the
| high temperature, otherwise you WILL get premature
| failures in bulbs that will last for years in ordinary
| lamps.
|
| https://duckduckgo.com/?t=lm&q=led+bulbs+enclosed+fixture
| +ra...
| outworlder wrote:
| > Any much older than that need to be checked out-of-
| circuit for ESR and then capacitance
|
| And that's a very time consuming and somewhat risky
| operation on an old machine you want to keep running.
| Some old PCBs are quite fragile.
|
| I wish there was a way to test capacitors without
| removing them.
| 83 wrote:
| Bipolar electrolytic capacitors are a thing, I recently had
| to solder up a handful of them in some audio circuits.
| nuancebydefault wrote:
| Once you have experienced blowing up a reversed elcap you
| will never forget its orientation. I never understood though
| what makes it leak current and hence heat up.
| kevindamm wrote:
| There's an aluminum oxide layer as a coating on both the
| anode and cathode inside the (electrolytic) capacitor.
| Under forward voltage it will gradually thicken but under
| reverse voltage it dissolves and causes a short. This
| increases the temperature which causes hydrogen ions to
| separate and bubble through the material, increasing
| pressure within the capacitor package until it bursts.
| marcosdumay wrote:
| Modern electrolytic caps don't burn like they used to.
|
| The last few times I made a mistake, there wasn't even an
| explosion, even less a short-circuit. The thing slowly
| boiled and bubbled or unfolded.
|
| Anyway, it blows up because the capacitor's insulation
| layer isn't some stable material, it's a tiny oxide layer
| built over the metal plate by anodization. If you put a
| high voltage on it with the wrong polarity, you reverse
| that anodization and short the liquid and the metal
| electrodes.
| rasz wrote:
| Commodore struggled with same mistakes on negative rail in Audio
| section, but also somehow on highend expensive CPU board.
|
| https://wiki.console5.com/wiki/Amiga_CD32 C408 C811 "original may
| be installed backwards! Verify orientation against cap map"
|
| A4000 https://wordpress.hertell.nu/?p=1438 C443 C433 "notice that
| the 2 capacitors that originally on A4000 have the wrong
| polarity"
|
| Much worse is Commodore A3640 68040 CPU board aimed at top of the
| line A3000 and A4000
| http://amiga.serveftp.net/A3640_capacitor.html
| https://forum.amiga.org/index.php?topic=73570.0 C105 C106 C107
| silkscreen wrong, early revisions build according to bad
| silkscreen.
| fredoralive wrote:
| Typical Amiga fanboyism and Apple envy, if a Mac does something
| they have to prove the Amiga outdid it. "Only one model with a
| reverse polarity capacitor? With Commodore it was a systematic
| issue!"
| bogantech wrote:
| > Typical Amiga fanboyism and Apple envy, if a Mac does
| something they have to prove the Amiga outdid it.
|
| I think we're envious that Apple did a better job of
| engineering their systems
| hettygreen wrote:
| They were probably expecting these to fail a few months after the
| warranty expired.
| omoikane wrote:
| I wonder if there were any bootleg boards that copied the
| silkscreen mistake, but didn't use those 16V capacitors, and
| ended up catching fire.
| PeterStuer wrote:
| In the mid 80's I was the head of the CS student chapter. We ran
| the computer rooms for the science faculty. We had a room with
| about 20 Mac 128k. I do not know where Apple sourced their
| capacitors from, but these were not A-tier. A Mac going up in a
| puff of white smoke was a weekly occurrence. We had a few in
| reserve just to cycle them in while they were out to Apple for
| repair.
|
| P.S. still my favorite Mac of all time was the IIcx. That one
| coupled with the 'full page display' was a dream.
| fredoralive wrote:
| With things like the Mac 128k, reliability issues may partly be
| down to Steve Job's dislike of cooling fans.
| m463 wrote:
| To be honest, cooling fans never get the attention they
| deserve and end up whiney or buzzy.
|
| That said, apple did a really good job with mac pro cooling
| fans where the shroud spun with the blades.
|
| I think it did better than the the best PC cooling fans like
| noctua.
| Melatonic wrote:
| I always built PCs with the largest diameter fans possible
| - not sure why so many things come with tiny fans. Loads
| more airflow with less noise and even if they do spin up
| fast the noise they make is much more pleasant.
| MBCook wrote:
| I was just thinking of the Apple III the other day.
|
| If I remember, jobs had them not include a cooling fan. As it
| would heat up and cool down the chips in the motherboard
| would work their way out of the socket. So one of the
| official solutions to try if you were having issues would be
| to drop it a couple of inches to try and get the chips to re-
| seat inside.
|
| Crazy.
| yetihehe wrote:
| On the other side, we had intern at our (very small) company
| and he used his own mac. One time he had to debug a mains-
| powered device. He decided that he will try connecting it to
| both mains AND programming dongle without separating
| transformer. He fried the dongle (it literally exploded,
| plastic lid banging on desk in sudddenly silent office is the
| most memorable thing), the company provided monitor and device,
| but somehow his private mac mini survived all this while being
| in the middle.
| jdbdbcjd wrote:
| That sounds fishy, even if the debugged device directly
| interfaced mains, the Mac doesn't. And even if it did, how
| high would the probability be that both machines were on
| different circuits with phases so much out of sync that it
| would matter?
|
| Unless I misunderstood your story
| yetihehe wrote:
| That device was a cheap wifi power plug, had cheap
| unisolated power supply, it was never intended to have user
| accessible electrical parts sticking out, so no need for
| isolation. In such cases device has common ground with ac
| voltage. I don't know all specifics, but NEVER connect any
| single terminal of 220V plug to your computer ground (usb
| ground in this case). When it's properly grounded, most
| devices will survive this. But somehow monitor connected to
| that mac didn't survive it. And several milliseconds of
| full 220V before circuit breaker reacted, made very thin
| traces in debugger pretty much vaporise and explode.
| nuancebydefault wrote:
| If i remember correctly, a lot of power supplies of cheap
| electronics have AC-coupled the low voltage side with the
| mains side. There's no physical wire, just a capacitor.
| You can often feel the AC when touching the 'safe' side
| of the adaptor.
| amluto wrote:
| Forget "cheap". As far as I can tell, many modern
| ungrounded power supplies, including Apple's, have enough
| A/C coupling from the line to the output that you can
| feel a bit of tingling when you touch a metallic object
| connected to the output.
| spockz wrote:
| How is this even allowed? My tv had it. My MacBooks since
| time memorial have it. They all feel "spicy".
| ChrisClark wrote:
| My Fold 5 has that feeling along the hinge when charging
| too, no matter the charger I use. I guess it's considered
| safe, but it's weird.
| wbl wrote:
| The Y capacitor is needed to allow the EMI to have a way
| to ground from the output rather than going out and
| getting radiated by the output lines.
| amluto wrote:
| I don't believe for a second that this is actually
| necessary in a way results in that spicy feeling. I do
| believe that it's far cheaper to use a Y capacitor than
| to come up with a better filter network that works well,
| though.
| wbl wrote:
| Common mode noise filtering is either going to be purely
| inductive or need a Y-cap. No other way around it.
| amluto wrote:
| One can build lots of things out of inductors and
| capacitors. I bet it's possible and even fairly
| straightforward to built a little network to allow high
| frequencies to pass from output to the two line inputs
| with low impedance but that has extremely high impedance
| at 50 and 60 Hz (and maybe even at the first few
| harmonics). It would add components, cost and volume.
|
| I bet this could be done at the output side, too. And a
| company like Apple that values the customer experience
| could try to build a filter on their laptop DC _inputs_
| to reduce touch currents experienced by the user when
| connected to a leaky power supply. Of course, the modern
| design where the charging port is part of a metallic case
| might make this rather challenging...
|
| (Seriously, IMO all the recent MacBook Air case designs
| are obnoxious. They have the touch current issue and
| they're nasty feeling and sharp-edged.)
| mgsouth wrote:
| Totally believable if the debugging device was doing
| something with a serial port. I once hacked something
| together to interface a PC serial port to a Raspberry Pi.
| The PC serial is real-ish RS-232, with negative voltages.
| The Pi side was just 0/3.3V positive. I had a nice 18-volt
| power brick laying around, and just split it's output down
| the middle--what was 0 volt ground was used as -9 volts,
| the middle voltage was now 0 volt ground, and the 18-v line
| was now +9 V.
|
| At first everything seemed OK. but when I plugged a monitor
| into the PI I Was Made To Realize a) the nice 18-volt PS
| really was high quality, and although it was transformer-
| isolated its output ground was tied to the wall socket
| earth, b) monitors also tie HDMI cable ground to earth, and
| so c) my lash-up now had dueling grounds that were 9V
| apart.
| Animats wrote:
| Does the -5V rail do anything other than power old RS-232 ports?
| zargon wrote:
| Macs have RS-422 ports, not RS-232. But, no.
| ethernot wrote:
| There are so many cases of this sort of stuff it's unreal. But it
| gets even stupider.
|
| I found one a few years back when I repaired a linear power
| supply. This required me to reverse engineer it first because
| there was no service manual. I buzzed the whole thing out and
| found out that one of the electrolytic capacitors had both legs
| connected to ground. They must have shipped thousands of power
| supplies with that error in it and no one even noticed.
| iknowstuff wrote:
| Name and shame!
| ethernot wrote:
| Voltcraft. Can't remember the model number.
| chrisdhoover wrote:
| Way back when a co worker was powering up a fire alarm control
| panel. Poof, capacitor popped and damaged his eye
| jcims wrote:
| I have a 3D printer where presumably a smoothing cap just fell
| off the X axis controller section of the mainboard. Didn't make
| a lick of difference in anything operationally. Still works
| great.
| robomartin wrote:
| It could be there to control emissions. You'd need to analyze
| the circuit to determine its purpose.
| jcims wrote:
| Very possible! I actually have a 100MHz scope and sdrs that
| tune from 9khz to 2ghz, could be an interesting distraction
| on the weekend to see if that axis is any noisier than the
| others.
| klysm wrote:
| Checks out, most boards are made with very conservative
| amounts of decoupling capacitance because it's way easier
| than dealing with random failures due to not enough
| capacitance
| jopsen wrote:
| I've understood that capacitors can be used for timing, or
| smoothing a voltage after a power regulator (I think).
|
| How/what does adding capacitance help with?
| pokeymcsnatch wrote:
| Voltage spikes from line inductance, voltage drop-outs
| from line resistance. Basically you have little
| reservoirs of charge scattered all around the board
| (current flow isn't instantaneous in a real circuit).
|
| It helps to always think of current draw in a compete
| loop, out the "top" of the capacitor, through your IC,
| and back into the ground side (this isn't necessarily
| what's happening physically). Shorter loop means less
| inductance, shorter traces less resistance.
| klysm wrote:
| Smoothing is part of the story: but the important
| question is what is causing the roughness? Switch mode
| power supplies have inherent output ripple that can be
| filtered, but that's distinct from transient variations
| in the load. Decoupling capacitors are used to provide a
| low impedance path at high frequencies i.e. fighting
| inductance.
| klysm wrote:
| That seems like one the least harmful mistakes you could make.
| Capacitors are sprinkled all over boards in excess's because
| it's probably better than not enough capacitance.
| andrew-jack wrote:
| Apple should be mandated to issue a recall for these
| motherboards.
| likeabatterycar wrote:
| The author seems to misunderstand PCB design flow. This is
| neither a "factory component placement issue" nor a silkscreen
| error. The error is in the schematic.
|
| The layout CAD is often done by a different team that follows the
| schematic provided by design engineering. Automated workflows are
| common. The silk screen is predefined in a QA'd library. It is
| not their job to double check engineering's schematic.
|
| The components are placed per the layout data.
|
| Both those teams did their jobs correctly, to incorrect
| specifications. In fact, the factory performing assembly often is
| denied access to the schematic as it is sensitive IP.
|
| If you're going to cast blame on a 30 year old computer, at least
| direct it at the correct group. It wasn't soldered incorrectly at
| the factory. They soldered it exactly how they were told to -
| backwards.
| rcxdude wrote:
| >The layout CAD is often done by a different team that follows
| the schematic provided by design engineering.
|
| Just as a note, this is a fairly archaic way of working
| nowadays. At my place schematic design and layout go hand-in-
| hand, and we rejected a candidate because he didn't do the
| latter. The main reason is layout is no longer an afterthought,
| it's a key part of the electrical design of the system, and
| there's little room for a tedious back and forth between the
| circuit designer and the person doing the layout about what
| traces are and aren't important to optimize for various
| attributes.
| jimnotgym wrote:
| And yet it is not at all unusual for a production engineer to
| spot these faults and pass them back to the design engineers
| for rework.
| rcxdude wrote:
| Also true! Most common when you accidentally screw up a
| footprint and it doesn't fit the part on the BOM. A
| backwards part is the kind of thing they're not likely to
| pick up on (if it's marked on the silkscreen incorrectly,
| at least), but some do.
| analog31 wrote:
| Indeed, and this is true in other engineering activities such
| as mechanical design as well. Possibly with the exception of
| very large shops, there are no draftsmen any more, and the
| design engineer also creates the production drawings. And the
| software lends itself to this. Schematic / layout, and design
| / drawing, are joined together in the design software. It
| would be very hard to make a mistake like the one in TFA
| today.
|
| Even the free software that I use -- KiCad -- would ding me.
|
| We make bigger mistakes instead. ;-)
| lmpdev wrote:
| I have my childhood LC II in storage
|
| I wonder if it has the same defect
| fishgoesblub wrote:
| If anything you should open it up to check for any leaking
| batteries/capacitors.
| magic_smoke_ee wrote:
| From around 2011-2015, I sometimes talked to an ex-Navy
| electrical tech who said he was also an early Apple rework tech
| in the SF Bay Area. He had no shortage of work fixing
| manufacturing problems, adding rework improvements, and building
| custom test equipment until they laid him off, outsourced his job
| to some random country, and then he was homeless until around
| 2016.
| nsmog767 wrote:
| not the Flux Capacitor?!?!
| johnklos wrote:
| It's a good thing that these machines don't even need -5 volts.
| With just the positive voltages provided, RS-422 still works,
| including LocalTalk.
|
| I think the -5 volts is only there in case an expansion card
| needs it.
| Waterluvian wrote:
| I spent my mid childhood on an LCIII. One summer my friend
| brought his Performa over and we tried to play 1v1 Warcraft 2
| over the serial port. LocalTalk or something alike?
|
| But it just never quite worked right. I remember how frustrated
| and confused my older brother was. The computers would sometimes
| see each other but would drop off so easily.
|
| Was this that?!
| etrautmann wrote:
| The first board I ever designed and had manufactured had a
| reversed tantalum capacitor on the power rails and exploded
| somewhat dramatically when powered up. Lesson learned!
| robomartin wrote:
| Brings back memories...
|
| About 30 years ago I designed my first PCB with frequencies in
| the GHz range. It was full of challenging transmission line paths
| with frequencies in the hundreds of MHz and above.
|
| I am still proud of the fact that all of the high speed signals
| worked as designed, with excellent signal and power integrity
| (the large FPGA was challenging). Emissions passed as well.
|
| I did, however, screw up one thing: DC
|
| I somehow managed to layout the DC input connector backwards!
|
| These boards were very expensive ($2K), so an immediate respin
| was not possible.
|
| I had to design a set of contacts to be able to flip the
| connector upside-down and make the electrons go in the right way.
|
| The joke from that point forward was that I was great at multi-
| GHz designs but should not be trusted with DC circuits.
| mhardcastle wrote:
| Why include that capacitor at all if it doesn't matter whether it
| works?
| rwmj wrote:
| 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, but can
| supplement the power on demand.
|
| So you can see why it probably didn't matter that this
| capacitor didn't work: It's only needed for rare occasions.
| RS-422 is a differential form of RS-232
| (https://en.wikipedia.org/wiki/RS-422) so being differential
| it's fairly robust against changes in load if they affect both
| wires. And the worst that can happen is you lose a few
| characters from your external modem.
|
| In addition, electrolytics can probably work when reversed like
| this, at least a little bit. It's not exactly optimal and they
| might catch fire(!).
| _whiteCaps_ wrote:
| Also known as the Madman Muntz theory of Engineering :-)
|
| https://en.wikipedia.org/wiki/Muntzing
| qingcharles wrote:
| I never knew there was a name for this :)
|
| When I was a demo coder my artist friend would just
| haphazardly go through all my assembler code and snip random
| lines out until it stopped working to improve performance.
| foft wrote:
| It is not just Apple that did this, for example here is an
| equivalent from Atari:
| https://www.exxosforum.co.uk/forum/viewtopic.php?f=17&t=1698
| 0xbadcafebee wrote:
| Anyone else a veteran of the Great Capacitor Plague? Seen more
| than one fire in the server room due to bad capacitors. "Burning-
| in" your server became literal.
| yborg wrote:
| I have a Quadra 700 of this vintage that hasn't been powered up
| in 25+ years. Kind of wanted to fire it up again to experience
| the glory of A/UX one more time, but sounds like I'd have to
| replace all the lytics :/
| mmmlinux wrote:
| Do it sooner than later, the cap juice loves to eat PCB traces.
| same with the clock batteries, get those things out of there.
| chefandy wrote:
| 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.
| mikewarot wrote:
| I've found a ground lug in a Kilowatt Grounded Grid amplifier...
| that didn't ground the grid.
|
| I found a bad solder joint that looked ok, but was intermittent,
| and had been that way, in a Television built in 1948 and used for
| decades.
|
| Bad design and assembly goes back forever, as near as I can tell.
| alain94040 wrote:
| Sounds like the person who designed the board followed a very
| simple and wise rule: always connect the negative side to the
| ground. Can't go wrong with that...
|
| until you have to deal with negative voltage (-5V). Another out
| of bounds bug.
| PcChip wrote:
| Didn't this also happen on some Asus motherboards a couple years
| ago?
| Karliss wrote:
| That one was Asus ROG Maximus Z690 Hero ~2years ago.
| 1oooqooq wrote:
| what apple era are those machines? is this before or after Jobs
| shafted the engineering department on the sale and Woz had to
| give them bonus to keep them on the factory?
| sroussey wrote:
| I have an original Mac that no longer turns on. I bet there is a
| capacitor to replace. This is giving me the energy to go look for
| it!
| MBCook wrote:
| There's a very good chance the battery has leaked and caused
| quite a mess. Well capacitors are a problem the battery is the
| biggest one.
___________________________________________________________________
(page generated 2024-11-27 23:01 UTC)