[SOLVED] USB ports have power when monitor HDMI plugged in

sarwar.khalid7

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Feb 25, 2018
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So recently my GPU died and I have been doing diagnosis on my computer to find if something was wrong. Last night I discovered that if I plug in my Rival 650 Wireless Mouse into a usb port with the PC and PSU turned off, the lights on the mouse start blinking meaning the USB port actually has power. After a bit of tinkering I discovered that if I unplug my HDMI then the lights turn off, and if I plug the HDMI back in the lights on my mouse turn on again. Since my GPU died I'm using my igpu.

Is this normal behaviour? I assume the HDMI is sending a voltage back into my mobo and this is where the USB ports are getting power even though the PSU is off, and maybe this is what killed my GPU?

Any insight/advice regarding this is appreciated.

SPECS:

CPU: Ryzen 2200g
RAM: Trident Z Royal 8GB x 2
MOBO: Gigabyte A320m
PSU: Antec Neo Eco Modular 650Watts
Monitor: Gigabyte g27f
My GPU that died was a XFX RX580 8GB
 

Colif

Win 11 Master
Moderator
But it could potentially damage a component right? So it is likely my gpu died because of this as I got this monitor fairly recently while I had the gpu since 2019.
the amount of charge coming down a HDMI cable is (in my eyes) unlikely to kill a GPU. As I said, its only probably enough to light up the lights on the mouse, its not enough to actually use it for anything. It is normal, it happens on every other PC and doesn't hurt the GPU or PC.

GPU more likely to die from other reasons that that. Like heat, bad components, Bad PSU.
 

Colif

Win 11 Master
Moderator
if i plug my rival 600 in when power is off, yes, I also get power.

If I plug pc in, and not use it right away, the RGB on my keyboard starts running

Its common for usb ports to have power when PC is off. its a feature. It lets you charge phones while PC is off.
PC is getting power via standby, through PSU, even though its off. Its not a lot but enough to turn on USB.
 

sarwar.khalid7

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Feb 25, 2018
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if i plug my rival 600 in when power is off, yes, I also get power.

If I plug pc in, and not use it right away, the RGB on my keyboard starts running

Its common for usb ports to have power when PC is off. its a feature. It lets you charge phones while PC is off.
PC is getting power via standby, through PSU, even though its off. Its not a lot but enough to turn on USB.
But im my case its getting very low power even when the PSU is literally unplugged from the pc. It's only getting the power when my hdmi from the monitor is plugged in
 

Colif

Win 11 Master
Moderator
hdmi can carry power but this seems to say its not enough to run usb more than maybe the rgb on them
The specification of the +5V charge is 50mA(according to wikipedia) This is even lower as USB before enumeration(100mA) Any device wouldn't be able to charge , or it will be very slow at 50mA (10x slower than normal USB port at full power, 500mA)
https://electronics.stackexchange.com/questions/28575/could-hdmi-be-potentially-used-as-a-power-supply-alternative-for-smartphones
If no other power sources attached to mb apart from the hdmi, seems to indicate it sends a charge to PC. I wouldn't expect it to be very big though as per above.
 

sarwar.khalid7

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Feb 25, 2018
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hdmi can carry power but this seems to say its not enough to run usb more than maybe the rgb on them
https://electronics.stackexchange.com/questions/28575/could-hdmi-be-potentially-used-as-a-power-supply-alternative-for-smartphones
If no other power sources attached to mb apart from the hdmi, seems to indicate it sends a charge to PC. I wouldn't expect it to be very big though as per above.
But it could potentially damage a component right? So it is likely my gpu died because of this as I got this monitor fairly recently while I had the gpu since 2019.
 

Karadjgne

Titan
Ambassador
Your psu is always on. It's either in working mode or in standby, it's never truly 'off' until you hit the psu switch or pull the plug, and even then it'll have a small amount of residual power stored in the caps until that's bled off.

This is done for a reason, windows has 'wake up' timers. Those are peripherals that will wake or turn on the pc at set times or when a key is hit or mouse moved etc. It's also what allows the momentary switch to turn on the 'pc' to work. In the old days there was a toggle switch instead.

So unless you restrict in bios the USB ports, they'll always have 5v power available. Part of the USB is data, so just because a rgb mouse has power available doesn't mean it's on, there's no data feed. Software controls the RGB, optical, laser etc.

Same goes for hdmi.
 

Colif

Win 11 Master
Moderator
But it could potentially damage a component right? So it is likely my gpu died because of this as I got this monitor fairly recently while I had the gpu since 2019.
the amount of charge coming down a HDMI cable is (in my eyes) unlikely to kill a GPU. As I said, its only probably enough to light up the lights on the mouse, its not enough to actually use it for anything. It is normal, it happens on every other PC and doesn't hurt the GPU or PC.

GPU more likely to die from other reasons that that. Like heat, bad components, Bad PSU.
 

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