Amazon cracks down on crappy USB-C cables and adapters


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HP's new logo a hit

Wow! Maybe we need to also ask why a USB port allows a bad cable to kill an entire PC.


“a writhing sea of dangerously low-quality third-party cables and adapters.”

Poetry, sheer poetry.


Not allowing the USB port to fully express itself, no matter the consequences, would be evil.


Nowhere is it stated how Amazon will determine if a USB-C product is compliant. The honor system sure won’t work. Do they have a product test department now?

And generic Chinese manufacturers have a nasty habit of changing the guts of electronics products weekly, depending on which chip is a penny cheaper right now. Amazon would have to test every single batch of products that come in the door.


A miswired port could kill just about any PC.


I’ve miswired plenty of serial ports in my day and never killed a MoBo doing it.


Miswired it to mains?


USB C provides a charging capability in addition to its data transfer channel. A high-current -5V surge (due to a miswired cable) into a poorly-designed power controller circuit can cause it to develop a short circuit, causing -5V to be sent to many other parts on the motherboard, which is Bad News.

It’s likely that the mobo designer never even considered that the USB port could supply a jolt of -5V on the power pins.


Meanwhile eBay will welcome them with open arms.


I was once issued an HP-85 microcomputer which, I was told, had entirely new guts. A technician had been asked to interface it to a number of 120VAC solenoids. Instead of attaching the correct adaptor to the digital I/O, he had found a PCB transition connector and wired the solenoids direct to the DIO pins. The only parts which did not have to be replaced were the case and the keyboard.


The scary part is that such people are allowed to vote.


It is actually possible to design serial ports to protect against the application of mains voltage, using a mixture of gas discharge tubes, fuses and thermistors. But that’s because the very low bit rate and high swing means that capacitance and series resistance can be tolerated. Generally speaking, the higher the bit rate and the lower the voltage swing, the harder it gets to protect a port.
I prefer separate power and signal connectors, but the market wants one connector to rule them all, even though it becomes a single point of complete failure.


The scarier part is that such people managed to get a job in a division of a respectable electronics company.


What about a DC-DC converter and optical or magnetic insulation? If the port gets fried, replace the port board.

Blame the plebes. The Market follows where they want to go. (Which is often where the Marketers goad them to, but anyway.)

The dumb masses are unwilling to learn that there are more types of connectors and what they are for. No wonder they want all concentrated to just one, collateral damage be damned.


I believe all USB types have 5V pins which can provide charging right?. The difference in the C is that it ups the amperage to 1.5 or 3 in addition to the baseline 900ma. It seems like the MoBo manufacturers would look for suppliers of USB receptacles which include overvoltage circuits like a zener diode. Really I’m just trying to say that a cheap cable should not be the death of a computer.


The most common reverse-polarity protection circuit for a DC input is a fuse followed by a big diode wired across the input, so that it will shunt the reverse polarity voltage to ground, thereby blowing the fuse.

More mobo makers might get into the habit of protecting USB ports in this manner, if they see a spate of returned bad boards with this symptom.


Everything old is new again… It’s like my old Tandy Color Computer expansion port projects that would fry the CPU – I always had an extra 6809 on hand.


Ebay has a rep for allowing Chinese sellers to run amok all over their selling boards, while providing as much buyer protection as a decade old condom for purchases from the far east. The rule of thumb now is not to buy anything crucial in any way from sellers in China, Taiwan, Hong Kong, etc. You may get lucky, or you may fry your computer.


Optical and magnetic connections don’t achieve the bit rate of modern serial protocols. It never ceases to amaze me that thirty years ago (showing my age) advanced, expensive and fiddly ECL was needed to get a miserable 500Mb/s down terminated coax with SM series coax conenctors, nowadays we are cheerfully chucking hundreds of megabytes per second down a serial connection made with cheap twisted pair and a bit of bent metal and plastic.

BTW I got a 2M USB-c connector from Amazon using the Google guy’s recommendations and it is absolutely fine.