
Bad USB-C cable destroys laptop - mrb
https://plus.google.com/+BensonLeung/posts/aFWWeiybe4P
======
AdmiralAsshat
HN has previously had a story on the author, a Google engineer who tests USB-C
cables on Amazon to make sure they're spec-compliant. He does some amazing
work:

[https://news.ycombinator.com/item?id=10508494](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.

~~~
digi_owl
Frankly the C plug spec seems overly convoluted.

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.

~~~
teraflop
> 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.

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.

~~~
knughit
A world with smart cables is a dumb world. I want smart devices/adaptors and
cheap dumb cables.

~~~
wtallis
USB cables aren't smart cables by any stretch of the imagination—not when
we've got standards like Thunderbolt. A single resistor is not unreasonable
complexity on top of the requirements to get the pinout correct.

------
earlz
TL;DR; USB-C cable had GND tied to Vbus and Vbus tied to GND (opposite as it
should be)

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

~~~
krapht
Why would you design in reverse polarity protection? It adds cost, and the
mechanical connector already makes it impossible for VDD to short to GND in
USB type C because of its rotational symmetry.

~~~
andrey-g
I constantly have Vdd shorts due to ground loops when measuring stuff. But a
more frequent case is worn out cables (every lightning cable I've owned has
eventually broke).

Its not rare enough of a failure mode to ignore.

~~~
krapht
Yes, and that's why the USB spec puts the burden of protecting against
electrical shorts on the controller. The device side shouldn't have to worry
about trying to shunt 100 Watts of power somewhere.

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.

~~~
mikeash
If you stop the current from flowing, you don't have to shunt any power
anywhere.

You'd have to open the circuit in the face of 5V of potential hooked up
backwards, not really a tall order.

~~~
krapht
I don't want to be a broken record, but you're right, not a tall order, but no
it's unreasonable on account of cost. It's impossible for USB C to be hooked
up backwards by its mechanical design, so why guard against it? The high-side
transistor to prevent reverse polarity faults could be 3 to 4 cents in
manufacturing cost! It's also not trivial to make sure that transistor trips
fast enough to prevent all your low-voltage ICs from being destroyed.

~~~
mikeash
Sure, but the magnitude of that cost matters a lot. You were saying a dollar
or two in raw materials to protect against 100W, now you're saying three or
four cents. A few cents to protect hundreds of dollars in equipment from
electrical faults seems worthwhile to me.

~~~
teraflop
That makes sense from the consumer's point of view. But imagine you're a
manufacturer, producing USB device controller chips by the million. Would you
really be willing to spend tens of thousands of dollars to protect against a
failure mode that can only happen due to some other company's extreme
negligence?

~~~
knughit
Tens of thousands of dollars total is far less than it costs a company just to
moot the question.

------
cornellwright
I wonder if this one cable was miswired or it's something consistently wrong
with the product. Either way that something like that could make it out of the
factory demonstrates terrible or no QA/QC.

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.

~~~
Perixoog
>I wonder if this one cable was miswired or it's something consistently wrong
with the product.

He bought more to find out:
[https://plus.google.com/+BensonLeung/posts/EBGMagC46fN](https://plus.google.com/+BensonLeung/posts/EBGMagC46fN)

~~~
simoncion
> He bought more to find out:

I don't think so. From TFP:

"Here are some pictures of the torn down SurjTech 3M cable that fried my
Pixel."

Cable, singular. :)

~~~
Trellmor
From one of his comments

>I ordered one more of each of Surjtech's products before they pulled their
listing today, so yes.﻿

------
kyrra
For those unfamiliar, this person (Benson Leung) is a Google employee that has
been testing USB-C cables to make sure they match the specs. His efforts were
previously discussed on HN[0].

[0]
[https://news.ycombinator.com/item?id=10508494](https://news.ycombinator.com/item?id=10508494)

------
guan
Reverse polarity protection is often not done with diodes for the reasons
explained. It is more common to use a p-channel MOSFET (or ideal diode
controllers when there are multiple power sources) when more than a trivial
amount of power is used by the design. They are not cheap when properly sized,
but are not ruinously expensive either and are not too large for most designs.

~~~
mindslight
There should be a crowbar diode between the rails. If the design is too cheap
for an input fuse, the source will limit/disable the short current.

~~~
klodolph
Crowbar isn't a diode, and it doesn't protect against reversed polarity, and
it's a bad idea on the input because you're relying on the other device to
limit current properly, when it's the other device which got the voltage wrong
in the first place.

~~~
mindslight
It acts like a literal crowbar, so why not call it a crowbar?

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.

~~~
klodolph
I'm saying a crowbar isn't a diode, and you're saying that you should call a
crowbar a crowbar? Color me confused. Usually a crowbar is a circuit with a
triac or SCR in it designed to protect against overvoltage.

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.

~~~
mindslight
Crowbar is a general concept - a short across a supply. A diode across the
rails acts as such, so I referred to it as a crowbar. I'm familiar with SCR-
based active crowbar circuits - what we're disagreeing about is narrow-
prescriptive versus wide-descriptive usage of a term.

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!

~~~
krapht
Ugh. Am I the only one who appreciates cheap things for what they are? Over-
engineering something is a bad thing, just as under-engineering it is too. It
makes things more expensive than they have to be.

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?

~~~
simoncion
> It makes things more expensive than they have to be.

Consumer electronics are -generally- _ridiculously_ cheap these days. I
welcome more "overengineering", even if it drives up the cost somewhat. :)

~~~
XorNot
The problem is cost != quality in any reliable way any more.

~~~
simoncion
That's an entirely separate issue from the one that my comment speaks to. :)

------
Spooky23
I think at some point Amazon should take some heat. They should at least de-
emphasize uncertified cables or require vendors to have licensed the USB logo.

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.

~~~
pluma
Amazon in Germany happily sells you power strips / connectors you can't use in
Germany without effectively voiding your insurance if your house burns down
(e.g. T-connectors that let you connect two Schuko plugs to a single wall
outlet without a cable).

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.

------
gpvos
Seems to be a kind of bait-and-switch operation, see this G+ comment by Lance
Nanek: _> >It's pretty common on amazon for some good items to be shipped to
get some good ratings, then for the seller to replace them with cheap, almost
non-functional, shoddy replacements. It's happened to me before with bicycle
equipment (pushing the button on a rear light pushed right through the casing,
etc.). So it's entirely possible you got a good one from their initial
offering, then they started selling something else.﻿<<_

~~~
knughit
These are the wonders of globalization. USA consumer protection laws don't
apply to foreign manufacturers using noname brands.

~~~
aikah
> These are the wonders of globalization. USA consumer protection laws don't
> apply to foreign manufacturers using noname brands.

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.

------
cocoflunchy
Interesting that most of the reviews for Anker and Aukey products on Amazon
have a variation of the same "I was provided with a free sample of this
product in exchange for my unbiased professional review."

~~~
greedo
How on earth do you think the tech review industry works? 99% of the reviews
you've read utilize free gear provided by the vendor. Some publications have
taken steps to curb potential excesses, but at least when I was freelancing
(2000-2005), almost all writers were provided gear for free, and allowed to
keep said gear.

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.

~~~
wtallis
There's a big difference between giving review samples to journalists to
review and publish on their own sites, and giving samples to be reviewed in
bulk on Amazon in the same context of customer reviews and aggregated together
with the same scores, with only a footnote of disclosure. Getting review
samples isn't the problem; the reviews are just being published in the wrong
manner. It's particularly inexcusable that the reviews solicited in this
manner are eligible to be tagged as "verified purchaser" reviews.

~~~
greedo
The "Verified Purchaser" tag is just so that people know the reviewer actually
received and ideally evaluated an actual unit, as opposed to a sockpuppet
review. What's your issue with his review? He actually reviewed the actual
units, compared them to the specs, and gave his professional opinion. All in a
place where it can do the most good, as opposed to posted to some defunct
Google blog.

~~~
wtallis
I think you lost track of the context. Benson Leung's reviews aren't the ones
including the disclaimer; he probably is spending his own (or Google's) money
to actually purchase the products. This is different from the astroturfing
spammers whose reviews are tagged as "Verified Purchaser" but the text of the
reviews shows that they didn't have to actually purchase the product. Those
spam reviews are rarely anything but vacuous and are certainly not
professional opinions in the same sense as Benson Leung's.

------
nalllar
The item appears to have been removed from amazon now.

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...](https://www.amazon.com/SurjTech%C2%AE-Standard-Adapter-Devices-
Macbook/dp/B01937P0O6/)

~~~
totalart9000
Question is, did they pull it for real or did they only do so to relist it
without having that review show up?

------
protomyth
Breaking test equipment should probably force a recall by itself. I wonder
what the Amazon procedure is for reporting faulty items?

~~~
mindslight
Yes, a recall of the "test equipment".

~~~
protomyth
I'm pretty sure you can blow up any test equipment with a sufficiently screwed
up test subject.

~~~
mindslight
Sure, but reverse voltage should be nowhere near sufficient.

~~~
sangnoir
Do you mind explaining why? Short circuits are common, and are mitigated
against. Reversed voltage is exceedingly rare, especially for USB C with
mirrored contacts.

~~~
mindslight
The purpose of test equipment is to diagnose weird situations - hence why OP
broke two of them trying to understand what was happening. Its requirements
are to be as robust and transparent as practical. The other end of the cable
could likely be bare wires connected ad-hoc with alligator/mini clips.

FWIW because the USB PD device is connecting two separate grounds, this same
failure could have happened from a single broken ground wire.

~~~
sangnoir
> The purpose of test equipment is to diagnose weird situations...Its
> requirements are to be as _robust and transparent as practical_

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.

------
tewha
SurjTech. SurgeTech? Seems an oddly appropriate name.

------
symmetricsaurus
Killed a laptop when plugging in my phone (with the old 30 pin connector).
Turns out a bit of foil from a wrapper had become stuck in the slot on the
phone.

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.

~~~
randyrand
I recently fried my laptop (still worth $500 on ebay and was $1800 new...),
from a cheap chinese pcie adapter.

I would love to know where or how I could repair it for and how much.

~~~
sedachv
You can find motherboards and other components on eBay.
[http://www.laptopinventory.com/](http://www.laptopinventory.com/) has a very
good catalog and excellent how-to videos. I have done parts replacement on a
few of my laptops (screens, keyboards, touchpads) and if you have ever added
RAM to a laptop the process for the other components is not really any
different.

------
scld
I guess he learned that step 1 should be using the ohmmeter and step 2 should
be plugging it into hundreds of dollars of equipment.

~~~
qb45
Do you really test each USB cable you buy like that?

~~~
wmf
We're talking about a guy whose job is to test USB cables.

~~~
fernandotakai
from what i remember, it was not his job -- he worked on products that have
usb-c components (like the pixel laptops) and wanted to make sure the products
on amazon were up to spec. you can see his reasoning here:
[https://plus.google.com/+BensonLeung/posts/LH4PPgVrKVN](https://plus.google.com/+BensonLeung/posts/LH4PPgVrKVN)

------
mmanfrin
His review has 1,120 positive votes out of 1,121; I don't think I have seen
_anything_ get near that high with just one 'unhelpful' vote.

[https://www.amazon.com/review/R2XDBFUD9CTN2R/ref=cm_cr_rdp_p...](https://www.amazon.com/review/R2XDBFUD9CTN2R/ref=cm_cr_rdp_perm)

------
ThinkBeat
He is brave to do his testing on such a nice computer. I hope he somehow gets
this covered. Amazon should pay him for his work.

~~~
bsimpson
He's a Google employee, presumably using corporate hardware to advance the USB
C ecosystem that the Pixel line is shepherding. I'd be shocked if Google
didn't let him replace it.

------
Tomdarkness
Surely this product should be removed from sale by Amazon until the
manufacturer can investigate?

------
outworlder
Reversed polarity? So, how does that even happen? Are they assembling cables
by hand, individually? And not testing them?

------
nathancahill
I tried to get a bit of dust out of the USB port of my MBP with a metal
tweezers. Sparks flew and that was the end of that laptop.

------
guelo
USB-C seems like a really bad standard if the cable can destroy expensive
electronics.

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.

~~~
tomswartz07
It's not the standard that's bad, it's the actual wiring of it.

That's akin to saying:

The US power grid is a bad standard because I wired up my house wrong and it
burned down.

~~~
cybrjoe
It seems more like saying:

The US power grid is a bad standard because I wired up my house wrong and it
burned the power station down.

~~~
mikeash
How so? The charger was fine (I presume, it's not mentioned either way), the
charged device got fried.

