I bought one of those magnetic USB-C cables and nearly fried something in my laptop with static electricity on the exposed plug.
The laptop failed to post, and the blinkenlights indicated a memory failure with error code 00001110.
The next day, it booted fine, which was odd. Memory tests indicate no issues.
warning symptoms that you are about to fry something: the display will glitch or suddenly turn black during use.
solution is to remove the USB-C cable and it’s detachable plug from the laptop.
Of course there are a few threads here about magnetic USB-C cables and in them, they do warn you not to use them, but I didn’t realize it was an issue until it was too late.
Part of the problem might be that people have seen or heard of apple’s magnetic connector. So they think that it should work fine with usb. Well, no. Apple’s magnetic connector was designed from the ground up for that purpose. Whereas USB was never made to handle the issues that such a connector brings. So it can damage or kill your devices. Just a matter of luck. Don’t use magnetic USB, unless you’re fine with the idea that your ports or whole mainboard can die at random.
Not sure if that fully resolves the issue, but I did modify the magnetic charger design so that instead of a usb-c extender there’s a “data blocker” inside, so that physically there are only the voltage, CC and ground wires connected. It does limit the card to only charge, but I wouldn’t want to send 10-40Gb/s through a wobbly connector to begin with.
Having tested several of those connectors and used one for more than a year, I dare to say: a warning might be justified, but along the lines of: I you buy such a thing, don’t be cheap. If the adapter costs less than 15€ and does not use gold plated contacts, stay away. Also, the better ones usually do not use pogo pin type contacts but some kind of contact bar.
I have, however, used high quality magnetic connectors between my dock and the FW13 for months with much success and no problems at all. At least full 20GBit USB is no problem (Tested with two external nvme enclosures). I did not yet test full Thunderbolt 40GBit yet, because TB hardware is quite expensive and I had no explicit needs for it so far.
The USB-C subreddit strongly advises against any magnetic adapters. But the Apple Magsafe 3 is usb-c on one side at least.
I think the problem is that all the affordable magnetic adapters you find on Amazon are not putting in the real expensive engineering needed to make it work safely and reliably … and if they did, how would you know, you’d probably pick another brand that looks the same but is cheaper.
I have a cheap third-party usb-c magsafe-2 cable from amazon, because I wasn’t going to buy another Apple magsafe-2 adapter (where the cable is permanently attached to the brick, and when it inevitably frays, the whole brick is e-waste). I’ve used it for a couple years on an old personal laptop, it works. But I have seen it arc a few times when the connector comes in askew. You can also easily tell that it behaves a bit different, the green led is instant, while on the real adapter it takes 1 second for it to come on.
My theory: Apple makes sure the voltage/current are not high during connect (and maybe disconnect as well? fast hardware detect?). Even though magsafe-3, while usb-c on the adapter side, is probably not usb at all on the laptop side, I think it’s possible for third-party adapters to make something similar, where there is a logic chip in each side of the adapter, which participates in the power negotiation, and ensures it does not flow during connect (and disconnect?). But that’s a lot more complicated, and I assume no third-party magnetic adapters do this. Would be cool to find one that did …
That is by far not everything. Summarizing what a few engineers said that sounds credible:
Pogo Pins do not have the signal quality for USB4 or the like.
And all the other things and the danger to devices stems from potential sparking or touching power pins to data pins or simply the wrong pins. And how much care went into the USB-C standard that that cannot happen.
Such that some pins connect first because they are longer. Which is very hard to do in a flat magnetic connector that is designed to rip-off to when pulled to the sides.
That the connector is long enough and pins are deep enough within it, that you cannot angle it in a way where the data pins accidentally touch power pins or come close enough for a spark, especially when ripping the connector off to the side (while those pins are still at high voltage and current is flowing).
MagSafe has a lot fewer pins that can be spread out more. It also does not include high speed data pins, where you cannot easily put surge protection on those pins to protect the electronics from temporary, wrong connections or sparks without killing the ability to transmit data at very high speeds.
Also, Apple can easily add additional protection circuitry that disconnects the power pins quickly, when the connector is about to ripped off. And surge-protect the connector appropriately. Sth. that is extremely difficult to fit into the small dongles that those magnetic USB-C connectors use.
So the thinking should be more: is the company that is producing those adapters in a jurisdiction touchable from where you are, such that they would actually replace your notebook, if their adapter should lead to frying your device years down the road? Now, of course they would not sell you sth. that has a 1:2 chance of damaging your device straight out of the box.
But do they care enough, have invested enough RnD, to make a connector as robust as USB-C that was designed to ensure such problems never occur for the lifetime of the connector, not even after years of plug-cycles?
(unless you physically damage and bend the USB-C connector of course and hammer it in anyways. Then there is not much to guarantee with that either).
