Re: USB audio device no longer showing up
On Tue, 2021-07-20 at 11:26 +0000, Dr. Jennifer Nussbaum wrote:
> I've been using a Schiit Modi 3 D/A converter for my main desktop
> audio for a year or two. In the last week, it's been sporadically
> vanishing from PulseAudio.
>
> It's normally plugged into a USB port on my monitor, which has
> several such ports, all of which work with other devices. When I plug
> it in, dmesg shows me:
>
> [2126764.183346] usb 3-3.4: new full-speed USB device number 75 using
> xhci_hcd
> [2126765.035388] usb 3-3-port4: Cannot enable. Maybe the USB cable is
> bad?
> [2126765.887389] usb 3-3-port4: Cannot enable. Maybe the USB cable is
> bad?
> [2126765.887461] usb 3-3-port4: attempt power cycle
> [2126768.319399] usb 3-3-port4: Cannot enable. Maybe the USB cable is
> bad?
> [2126769.171424] usb 3-3-port4: Cannot enable. Maybe the USB cable is
> bad?
> [2126769.171483] usb 3-3-port4: unable to enumerate USB device
>
> I get similar messages from other ports; other devices show up fine.
> This port is successfully providing power to the Schiit.
>
> Though "Maybe the USB cable is bad?" is a dubious-sounding message, I
> did swap out the existing random cable with a brand-new good-quality
> one, with no difference.
>
> I also tried to plug the Schiit into a Debian laptop, with the same
> results as above. Confoundingly, after this test, I re-plugged it
> into my monitor and it magically started to work -- it showed up in
> dmesg, it started to play audio.
>
> However, hoping it magically works isn't a good long-term solution.
> Is there any way to figure out what's causing this? Could it be a
> hardware problem with the Schiit? If so, how do I report it to them?
>
>
Hi,
according to my long and sometimes painful experience with USB-audio
interfaces I suspect that it is the internal USB connector in your
external interface that's failing. So hardware problem, indeed.
These connectors are 50¢ apiece, but unfortunately they are usually SMC
parts soldered directy on the print circuit board so they provide very
little resistance against the shearing tension implied by the USB
cable. I've just luckily been able to repair a € 500.- desktop
synthesizer from exactly that kind of damage. That was hard enough
despite the usage of a full-size connector on the extarnal side and
probably much more space to work than inside a portable audio
interface.
I've seen this kind of damage a lot in USB interfaces and usually
there's little hope of repair unless you put a lot of time and skill in
it.
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