Ha. You can now buy USB C-to-C dongles that add the 5.1K resistors on the CC lines that the manufacturers of whatever cheap noncompliant legacy device were too ignorant/lazy/stupid/greedy to include. Amazing.
@valpackett spare a brief explanation for someone unfamiliar with USB specs?
@matildalove to properly signal to a USB-C powersupply "I want to be fed 5V please" you need to connect 2 pins to ground through 5.1kOhm resistors. Some device designers don't pay attention and connect those two pins together and then to ground through 1 resistor, or skip them entirely. That will work if you use a dumb power adapter that doesn't check those (e.g. an old USB-A one and a A-to-C cable), but not with a better charger.
@matildalove This adapter probably just implements these two resistors and doesn't connect these 2 pins to the downstream device, so any power adapter will read it as "output 5V" and it'll work.
@valpackett Oh, for so cheap devices like the Nintendo Switch you mean?
@agowa338 LOL but no, the Switch is mostly fine actually. It actually supports PD, even. This is about the junk that treats USB-C ports as if they were just micro-B. Like my label printer that I thought just broke, until I eventually plugged in a C-to-A cable and it started charging again…
@valpackett Isn't this the resistor that is needed to initiate charging when the battery is completely dead?
Like I've had a few Nintendo switches here to repair just because their battery was drained too much for it to initiate the charging. After a "kick-start" it was fine again.
@agowa338 that's a silly issue, but no, if you have a smart device that actually talks PD over CC pins, it's not missing any resistors on those lines.
I don't fully recall the writeup of this issue anymore but the very first switches had also something with missing components for this. I think they fixed it in later versions.
But I'm quite sure there was something like this in the first ones.
I think it was this design issue here: https://headworx.slupik.com/2026/03/usb-type-c-dead-battery.html