[arm-allstar] One of two USB URIs dropping off

David McGough kb4fxc at inttek.net
Fri Jan 11 22:26:47 EST 2019

Hi Randy,

I run several systems with 2 or 3 URI's or other sound adapters. I don't 
see any software issues with this type of setup. As long as the hardware 
remains stable, these systems run fine.

Do both URI's stop working, just one, or a random pattern?  I assume the 
RPi3b+ stays up (no spontaneous reboots)?  What do you see in the kernel 
messages when the URI(s) stop working (dmesg command)??

What are the URI's attached to (what type of hardware)? Is the hardware 
all in a rack, or how is it laid out? How is the hardware powered 
(perhaps multiple power supplies?)??

Aside from the typical 5V power concerns with RPi boards we're all aware
of, the single biggest issues I've experienced with multiple URI's are
ground loops, where the ground potential is changing (and going thru the
USB ports!) at the computer. It's pretty easy to upset the CM1xy chips
this way and make them lock-up.

The URI lock-up problem was once a periodic concern for me when I used a
single PC computer with several URI's. Since I've RPi3 boards and a single
URI per board for my "hard to reach systems," I've not had a single
occurrence of this old issue.

73, David KB4FXC

On Fri, 11 Jan 2019, "Randy Neals via ARM-allstar" wrote:

> And we got about 3+ hours and one of the DMK URIs has stopped working (no

At this point, we have a Pi3B+, powered with a 3 Amp DC to DC converter,
and two DMK URIs connected.
The USB flash I has plugged into the PI was removed.

Continuing to isolate and sectionalize this to figure it out.


On Fri, Jan 11, 2019 at 5:53 PM Randy Neals <randy at neals.ca> wrote:

> 2 Hours without USB Flash drive. Repeaters/USB interfaces (2 URIs) still
> up...
> The USB Thumb Drive was a Verbatim Metal Cased "executive" series.
> https://www.verbatim.com/prod/usb-drives/everyday-usb-drives/metal-executive-usb-drive/
> Randy

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