usb devices have power after system off

daven1986 · 13 May 2007 at 14:20

when i turn off my pc, 2 of my usb devices still have power. a usb keyboard and a griffin powermate.

is there anyway to stop the mobo from providing power to devices when the pc is off? it is an msi neo2 platinum board.

thanks

daven

Oddw1re · 13 May 2007 at 14:23

turn off at wall

daven1986 · 13 May 2007 at 14:24

lol yes that is an option, but i was hoping that there was something less extreme

The Halk · 13 May 2007 at 14:58

I know my board (Abit) has jumpers on it for USB power. I always thought they were jumpers that allowed the PC to be powered up by a signal from them, but maybe it's what you're looking for.

daven1986 · 13 May 2007 at 21:13

could be thanks. i will look for a bios option too.

thanks

happy_2008 · 13 May 2007 at 23:07

My old computer had this problem didnt find a fix in the end for it either

Kemik · 13 May 2007 at 23:10

What OS are you running? I know Ubuntu does this.

Hades · 13 May 2007 at 23:28

I think it's quite normal and depends on your PSU. My old OCZ Powerstream did it too. But my current Seasonic doesn't (same motherboard, etc). The significant difference is that the Seasonic has a 5v pin blanked out on the motherboard connector. I looked it up when i got it and found that it was a legacy AT pin which they no longer support.

So reading between the lines I came to the conclusion that the missing pin is likely to be the reason I no longer get power when it's off. tbh I preferred it when there was power because I now have to have the PC on to charge my USB connected phone/PSP/satnav/etc.

daven1986 · 14 May 2007 at 00:13

yeah i can see that benefit, but my pda has a mains charger and the powermate has a bright blue light on

The Halk · 14 May 2007 at 00:36

daven1986 said:
could be thanks. i will look for a bios option too.

thanks

It's not a BIOS option on mine. It's a low level function of the motherboard, so it's on a jumper.

It'll also not be an OS function, no OS is loaded at this point.

And it's also not a PSU function, since USB is powered from the motherboard.

Hades · 14 May 2007 at 00:53

The Halk said:
And it's also not a PSU function, since USB is powered from the motherboard.

Disagree there. I don't know for a fact. But the lack of a 5v pin causing no power to a 5v USB connection indicates to me that the motherboard can have a bearing but so can the PSU. I suspect the missing 5v pin allows for voltage even if the mobo is turned off.

The Halk · 14 May 2007 at 00:59

Hades said:
Disagree there. I don't know for a fact. But the lack of a 5v pin causing no power to a 5v USB connection indicates to me that the motherboard can have a bearing but so can the PSU. I suspect the missing 5v pin allows for voltage even if the mobo is turned off.

Well, that's true, if the motherboard isn't getting the power supply it needs for it. But yours _should_ still be on, it's just that the PSU doesn't have the legacy connection.

What I don't know is if your motherboard should be generating the 5V itself and not relying on an out of date power connection....

Anyway, USB is powered from the motherboard. My motherboard stays lit up (can't reemmber if it gives power to the mouse) but I know a few LEDs stay on, and the network port flashes when the power is off, and I'm using a Corsair PSU which I assume lacks the same supply as yours does.

But anyway, my best suggestion is to look for jumpers on the motherboard.

SiriusB · 14 May 2007 at 01:19

The Halk said:
But anyway, my best suggestion is to look for jumpers on the motherboard.

And look for cardigans too!

The Halk · 14 May 2007 at 01:23

SiriusB said:
And look for cardigans too!

Yeah. Any kind of wollen products are likely to cause overheating, which will "escape" down the 5V line to your peripherals at power down.

misterPK · 14 May 2007 at 09:42

SiriusB said:
And look for cardigans too!

Are tank tops ok?

My oldish ABit KN8 has power going to the USB ports, its useful for charging my phone, but the red power LED on my motherboard is a bit bright and annoying in the dark.

PK!

daven1986 · 14 May 2007 at 19:28

well if i unplug the device, then plug it back it (all while system is off) then the light goes out, so im guessing that if it were a psu function then it would be on when plugged back in?