Bad USB-C cable destroys laptop
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https://news.ycombinator.com/item?id=10508494
I don't have any devices right now that use USB-C, but whenever I see a deal pop up for one, I usually check the Amazon listing to see if this guy has reviewed/certified the cable yet.
I recommend others do the same. It's not worth damaging your $800+ laptop because you wanted to save $10 on a cable.
https://docs.google.com/spreadsheets/d/1wJwqv3rTNmORXz-XJsQa...
http://smile.amazon.com/dp/B018F8BGLA
It's worth noting that the Nexus 5x doesn't do USB 3.1, so even if you get a fancy Super Speed cable like this one, you are still suck with slow charging from your computer's USB A port.
When you plug it in, turn it off, then back on. Down at the bottom, near the fingerprint, it should indicate the type of charging you're getting. I've seen three modes, and I apologize for not knowing the distinctions, but they're "charging slowly", "charging" and "charging rapidly".
Times are commensurate to the charge mode, and rapid charging is unsurprisingly quite fast.
Another thing that might be the case is if the OP is going from actual empty to full without turning it on, which should (to some extent) expedite charging as there is no discharge happening at the same time, maybe.
Each cable needs one of 3 resistors depending on them being a A/B-to-C cable, 1.5A C-to-C cable, or 3A C-to-C cable.
Note that the A-to-C cable may well be able to carry 3A, but it shall never use the 3A C-to-C resistor (what many of the cables he find as faulty does).
Note that all this resistor shenanigans are all independent of the Battery charging spec that has been around for some years, and also the Power Delivery spec that was introduced along with the 3.1 USB spec (can be used for all ports) and the C port spec.
Never mind that a C port has so many extra pins compared to a A or B port, that one would think that id-ing a A-to-C cable would have been as simple as looking for life on any of those extra pins.
No, for C-to-C connections, the resistance is provided by the host ("downstream-facing") port, not the cable. The resistor in an A-to-C cable is basically emulating the signal that would otherwise be provided by the host.
There's no such thing as a "1.5A C-to-C cable"; all type-C cables are required to deliver at least 5A. The limiting factor is the host, not the cable, which means the cable must not incorrectly advertise capabilities that the host doesn't support.
> Never mind that a C port has so many extra pins compared to a A or B port, that one would think that id-ing a A-to-C cable would have been as simple as looking for life on any of those extra pins.
That's exactly what the new CC pin is used for. Right now the spec says "legacy cables should connect CC via a 56kΩ resistor", but it wouldn't matter if instead the requirement had been "legacy cables should leave CC disconnected"; the issue is that cable manufacturers are ignoring the spec.
4.11 could really use a massive cleanup for readability it seems.
1.5 A is required to be supported by USB-C, while 3 A is optional. Everything over it is covered by USB Power Delivery, which requires a marking of the cable which of the 5 profiles are supported.
It's just as complicated as it needs to be. And for godssakes, the pin-out diagram isn't that complicated; it only has 24 pins! There's no excuse for flipping two of them. 24 pins is not beyond the pale of what we would reasonably expect manufacturers to be able to wrap their heads around.
http://bi9he1w7hz8qbnm2zl0hd171.wpengine.netdna-cdn.com/wp-c...
You use the pins on both sides to do four-lane DisplayPort, or DisplayPort and USB 3 at the same time, or Thunderbolt.
Honestly, I'm surprised that this isn't something that thelaptop and other such USB adapters aren't equipped to deal with. This is only slightly worse in my book than a USB adapter being fried from shorting the Vbus and GND pins together
The protection against reversed voltages like that would be a crowbar diode between Vbus and GND, to convert the negative voltage into a short circuit. But even if it had that reverse protection, if the current was high enough (since the negative voltage was from a charger, it's not unlikely) the diode could burn open, and then you have negative voltages again. And I don't know how common these crowbar diodes are; they probably are rare, since the USB connector is keyed so it can't be plugged "backwards" (the type C connector is mirrored instead, either orientation connects the pins the right way).
However there is other kind of protections like this : http://www.edn.com/design/analog/4368527/Simple-reverse-pola...
But when the polarity is reversed beyond the diode's voltage drop (that is, beyond -0.6V in your example), the diode is now the "right way" and conducts, limiting the reverse polarity voltage to the diode's voltage drop (in your example, it won't get below -0.6V).
However, that means that all the reverse-polarity current goes through the diode, in effect a short (like putting a physical crowbar across the battery terminals). If the diode holds long enough, the voltage source's short-circuit protection (be it a fuse, a polyfuse, or something else) should cut the current and all is (mostly) fine.
The basic USB spec requires that all ports be protected with a small self-resetting polyfuse for exactly this reason. I don't know if the Type-C or USB 3.1 specs includes something similar - I would assume so but perhaps the additional current capabilities made that infeasible.
http://elinux.org/Polyfuses_explained
A standard USB polyfuse usually resets pretty fast (as soon as it cools down) but they could take up to a few days. It's also possible the manufacturer cheaped out and didn't include a polyfuse, of course.
Rebooted, and the USB port did not work. Shut it down and left it for half an hour, and, yay, all working again.
Disassembled the adapter. Turned out to be a dummy used for display. No guts, just a steel bar across all four pins of the USB connector. Looked real from the outside.
It was a very, very stupid thing to do. Thank-you Apple for putting a self-resetting fuse in my MacBook Pro. Saved my idiot butt.
Current limiting doesn't magically protect powered devices from voltage reversal (-5V instead of +5V), so both the laptop and power delivery analyzer went poof.
They may have taken enough current to trip charger's current limiter, but then it was a bit too late.
Its not rare enough of a failure mode to ignore.
I mean this kind of protection is way beyond typical ESD protection due to the power involved. It would add a lot of cost to do this, maybe even a dollar or two in raw material.
You'd have to open the circuit in the face of 5V of potential hooked up backwards, not really a tall order.
Because cabling can fail in other ways. A short could be caused by mechanical damage to the cable anywhere along its length. It would be nice to have a host that doesn't burn up in those scenarios seeing as they are already required to protect the bus.
If it is at the power supply end, all bets are off. If your USB charger fails short prepare for mains voltage to absolutely fry anything and everything connected to it and a negative voltage is the least of your worries. In the cable, a miswiring is seriously negligent and I see no reason why it should be designed around.
It's not abnormal to add protection that isn't needed when everything works properly. As noted elsewhere, the USB spec already requires resettable overcurrent protection, for example.
The 3-4 cents is for specifically, reverse polarity protection when somehow, a -5V differential is applied to device power inputs.
This cheaper solution only narrowly addresses this particular power fault, and no others.
Do I assume correctly that a fuse for overcurrent protection wont act quickly enough to save the hardware in the event of reverse polarity?
what was wrong was that the Vbus on one end was hooked to the GND of the other end.
If you're doing lab work, it's really easy to get weird potentials on various lines. I almost never plug anything like an Arduino directly into my laptop without a powered hub in between.
I assume I'm a klutz. So, I take steps to minimize the damage when something happens.
Personally, I've switched over to using USB 3.0 hubs. They supply more power and seem to be better built.
I know because I've triggered it doing something with an arduino.
I've never used the Twinkie but it looks pretty cool. This shows that it may be worth adding some simple protection to the circuit to prevent simple miswires from damaging it or the host PC.
He bought more to find out: https://plus.google.com/+BensonLeung/posts/EBGMagC46fN
I don't think so. From TFP:
"Here are some pictures of the torn down SurjTech 3M cable that fried my Pixel."
Cable, singular. :)
>I ordered one more of each of Surjtech's products before they pulled their listing today, so yes.
There are likely already plenty of diodes across the rails (the body diodes of the chips), so without a fuse the power is already limited by just the source. IMHO you might as well try and protect the circuit from foreseeable power-limited situations like frayed cables and the OP.
This isn't about frayed cables. Frayed cables don't do this. This is about a cable which is wired the opposite of the way it should be. A minimal protection circuit is probably going to cost around $0.20 in quantity (Si2323 on Mouser). For a $500 Chrome Pixel C, the protection circuit is worth the effort if more than 1 in 2,500 ($500 / $0.20) laptops would fail due to charger cables with reversed polarity.
If you think that fewer than 1 in 2,500 laptops will fail this way, then don't bother.
Most frayed cables are going to simply short or open, but the right combination of such would cross wires. But sure, they're going to be rare.
On a $500 device I would indeed expect a modicum of robustness against negligently designed cables and other weirdness. I mean, I'm not the only one that doesn't have a cable tester and buys cables without a connected-equipment warranty, right? Historically, electrical connections have been designed to deal with weird shit. Do you think you could kill an RS-232 port with any permutation of connections?
Of course the cost metric explains why devices are no longer robust. In fact the manufacturer only has to worry about in-warranty failures, and furthermore only the ones they can't blow off as "user error". Just because devices are designed for the 4 month (or whatever it's down to) upgrade cycle, doesn't mean that informed consumers shouldn't call out designers of such equipment as the cheapskates they are!
There's an art to designing something to last for no longer than it has to, and to use not a single part that isn't necessary. How much worse would our lives be if we had to pay industrial/commercial prices for all of our goods?
Consumer electronics are -generally- ridiculously cheap these days. I welcome more "overengineering", even if it drives up the cost somewhat. :)
If you buy a power strip, even a cheap one, you at least get some assurance that it is UL rated and probably won't burn your house down. USB isn't just a keyboard connector anymore... We should have some assurance that cables are legit and safe.
Granted, for some of them it adds a small disclaimer "Only for export" but let's be honest: if you're selling to consumers, you're not selling for export.
That's false if you buy stuff on Amazon. That's true if you buy goods on a chinese website. USA consumer protection laws certainly apply since Amazon is a US corporation. Otherwise Amazon would be selling controlled substances like it's an Rx.
Ethical journalists can attempt to ignore the impact of gratis equipment, but it's difficult in the best of situations. Just as difficult as trying to ignore the impact of a "helpful" PR department. Apple was particularly good at this; I was provided with every version of the iPad for reviews. Once Apple got over their death march, this dried up, and dealing with their PR firm became tedious. HP provided notebooks, PDAs, anything, with no expectation or real system for returning equipment. The only vendors I ever dealt with that were strict about returns were Kodak/Canon with their DSLRs and lenses. These were normally around $10K or greater, so I was not surprised at all.
Bias is implicit in any review where the publication isn't purchasing the items it reviews. I'm not sure how Sweethome and the Wirecutter work, though I know they make $$ off of purchase referrals through Amazon.
I had a similar issue with a lightning cable purchased on Amazon that claimed to be a licensed Apple cable, but wasn't. I plugged it into a real Apple charger, went to plug the other end into my iPhone and sparks flew out of it as soon as it got close to the phone.
Clicking the link to the item[1] on the review page leads to a 404.
[1]: https://www.amazon.com/SurjTech%C2%AE-Standard-Adapter-Devic...
FWIW because the USB PD device is connecting two separate grounds, this same failure could have happened from a single broken ground wire.
That doesn't set a clear-cut boundary, does it? What seems practical to you might be impractical to the test equipment maker - especially when cost is considered. Should the test equipment be robust enough to handle 1000+ amps? I'd say no, someone else (maybe even you) might say yes.
Since this was in the bad old day the laptop was fixable for under $200 so it wasn't too bad.
Still, makes sense to keep an eye on what you plug into your computer.
I would love to know where or how I could repair it for and how much.
https://www.amazon.com/review/R2XDBFUD9CTN2R/ref=cm_cr_rdp_p...
EDIT: Even if the cable is wired and built correctly (which is apparently difficult for manufacturers to get right), cables fray and tear all the time. I foresee a lot of dead electronics upcoming.
As for cables fraying, the most common result is an open (an unconnected wire). If two of the wires get damaged at the same time, you might get a short (and the USB standard mandates that a short causes no damage to devices). But reversing a pair of wires? It's ridiculously unlikely that fray and tear on a cable not only severs a pair of wires, but also reconnects them backwards!
That's akin to saying:
The US power grid is a bad standard because I wired up my house wrong and it burned down.
The US power grid is a bad standard because I wired up my house wrong and it burned the power station down.