Dear Lazyweb,

I want a Thunderbolt 3 hub with these properties:

  1. Can run video through it.
  2. Externally powered.
  3. When external power is cut, connected devices lose power, rather than continuing to be powered by the host.

Does this exist?

The goal here is not "be a hub" but "be able to power cycle the device", since my piece of shit Blackmagic UltraStudio Recorder 3G often loses its mind and stops functioning unless I physically unplug it from the Thunderbolt cable and re-plug it.

Rebooting the host computer is not an option, and I can think of no other way to remotely reset this piece of shit, since it is powered from the Thunderbolt cable, not an external power supply.

But I do have a PDU that lets me remotely cycle plug sockets.


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21 Responses:

  1. DV says:

    You need something like this, but also TB3 compatible?

    30cm USB C Male to Female On/Off Switch Cable YOUCHENG for Raspberry Pi 4 (2-Pack)

    Alternatively a hub that has power buttons to each hubbed device?

  2. Tyler says:

    Don't know for sure that it would work, but can you use a dremel to cut the power line trace on the pcb at the host connector?

    • jwz says:

      You let me know as soon as you've tried that.

      • Carlos says:

        There's a better - and less destructive - way.  I use this to prevent the electronics in a self-powered device connected to an upstream computer from being back-powered from the machine when the device is turned off.

        You can cut the VCC wire inside a USB/Thunderbolt cable if you're careful.  I cut the sheath about 180 degrees around a section of cable about 20mm long.  Leave it attached on one side so it's a flap and you can fold it back down when you're done.  Identify the correct wire - ideally the wire colours will be sane, but it's a crapshoot.  Cut a small section of it out, wrap everything back up and use tape or heatshrink to hold the cable together.

        Everything works perfectly, but nothing will be powered from the upstream device - so only the hub's power supply matters.

        You're only hacking a $10 or $20 cable rather than the PCB in your device or computer, and since you're only cutting a wire (and are technically competent) you can't short anything together.  The worst that happens is you cut the wrong wire and the cable stops working.


  3. Brian says:

    These two docks do not appear to do what you want.

    This was tested by me just now with a Sonnet Solo 10G TB3 adapter (for the TB3 docks) or a Lacie TB2 powered drive (for the TB2 dock). The interface didn't disappear from the bus and the ethernet connection didn't lose link to the switch. And the drive remained mounted.

  4. JStanton617 says:

    The only true Thunderbolt powered device I have is my macbook, but when I pull the power to my CalDigit TS3 Plus dock, my phone (USB-C to lightning cable) in any port stops charging.

    Specs say the secondary Thunderbolt port supplies 15 watts. Not sure what your requirements are.

  5. summersclone says:

    I have one of these:

    I just unplugged it and the USB mouse I have plugged into it turned off. I can do other tests if you'd like.

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