HELP: It appears that my amp fried my USB ports
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CaptainFantastic

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Last week I purchase a Grace Design m900. I had done some extensive research on the sound and other attributes of this model and I can already say that I am satisfied with what I hear and the build quality.

On Saturday evening I had something strange happen and I would like see if anyone had this happen to them or could provide more insight into what happened. So far this article is the closest (www.cnet.com/news/usb-type-c-cable-problems/# - see also the comment to this article regarding a 5V related short) that I found to what happened to me, except the m900 does not use USC-C ports, it uses Type A to micro USB cables made by Monoprice (www.gracedesign.com/products/m900/m900.html).

Here is what happened:

A. I had the short m900 USB cable connected to one of the USB ports of my ASUS ROG STRIX Z370-H GAMING motherboard (one of the red USB 3.1 ports seen in the picture on this page - www.asus.com/Motherboards/ROG-STRIX-Z370-H-GAMING/ ). In the other USB 3.1 port I had my Corsair mouse plugged in.

B. I had the long m900 USB cable connected to the power adapted and this was plugged in to my reliable, surge protect power strip.

C. None of the two cables were plugged into the micro-USB ports on the m900. Then I did one of the following, I don't remember in which order:

Possibility #1
a) I plugged the micro-USB end of the long USB cable connected to power into the 5V, 2A port on the m900.
b) After this I plugged in the micro-USB end of the short USB cable connected to the PC into the USB 2.0 on the m900.

or

Possibility #2
a) I plugged in the micro-USB end of the short USB cable connected to the PC into the USB 2.0 on the m900.
b) After this I plugged the micro-USB end of the long USB cable connected to power into the 5V, 2A port on the m900.

D. A few seconds after this my Corsair mouse went dead and it became clear that both 3.1 USB ports (the red ones in the diagram) died. This remains the case today, two days after, and after several reboots.

E. Both the mouse and the m900 work fine when connected to any of my surviving USB ports.

Questions:

- Do you know what caused this?
- How can I prevent it from happening again? I am thinking I should first have the m900 powered up and only then connect it to the PC if Possibility #2 above is what happened when I fried my USB ports. But should this have been possible?
- Other thoughts? Possibility of fixing the dead ports (they are encased in the motherboard as seen in the picture)

Many thanks for any helpful thoughts.
 
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CaptainFantastic

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Update on this:

I had initially reinstalled the USB drivers and the two ports were still not responding. This is why I had assumed they were dead. But Grace Design provided a link to the latest 3.1 drivers and a couple of other tips like checking the power management settings for auto-disable features. After some tinkering, I am happy to report that the USB ports are back to life. Issue resolved, everything seems to be in order. It must have been a weird, rare situation because the m900 worked just fine before and works just fine now on this computer and the work one.

I was impressed with how quickly their customer support service responded.
 
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Svenrolic

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Update on this:

I had initially reinstalled the USB drivers and the two ports were still not responding. This is why I had assumed they were dead. But Grace Design provided a link to the latest 3.1 drivers and a couple of other tips like checking the power management settings for auto-disable features. After some tinkering, I am happy to report that the USB ports are back to life. Issue resolved, everything seems to be in order. It must have been a weird, rare situation because the m900 worked just fine before and works just fine now on this computer and the work one.

I was impressed with how quickly their customer support service responded.
Could you please clarify the exact cause of this issue if possible? It is very likely that another user will stumble upon this thread with the same issue at a later date. Thank you for posting your resolution. Its good to know the support team here was easy to work with.
 
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CaptainFantastic

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Not entirely sure what caused it. Best guess now is that a safety feature kicked in and disabled the ports preventively.

Customer service explained to me that the data port of the unit will only draw a max of 500mA (the USB 2.0 spec). If I connected the 5V 2A input second (possibility #2 above), they said that in that case it would have been possible for the unit to draw up to 2A from the port, but only
if the volume was at maximum. I think I had it at 44 volume, because the m900 has a feature where you can set the boot-up volume. I suppose there is a 5% chance that I turned up the volume before plugging in the 5V 2A input, playing with it for some reason. Unlikely, I don't recall doing that + the unit volume wheel is very well done and turns up in 1/2 unit increments, one would have to do 3 full 360 degree turns to get to 100. But it sounds like if I did, this could have triggered the USB port safety feature?

They also said that the m900 idles around 380mA in high power mode, so shouldn't have caused any damage to the port. For possibility #1 (connected the external power to the 5V 2A input first), they said that the unit would configure itself as self powered and shouldn't draw any power from the USB data port. Finally, in either scenario, it shouldn't be possible for the m900 to draw more than 500mA from the data port. Each USB input is isolated with a current limiter.
 
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