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we dont have 5v on usb after shutdown, why are we trying to power it from psu if psu has no powerout after shutdown? Answered

we dont want power on usb port after shutdown we connect it via molex molex after shutdown doesn't have power too? if we dont want to supply 5vdc from usb after shutdown, why are we connecting it to PSU which doesn't supply 5vdc after shutdown either?

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user
andy (author)2010-12-15

You can pull 5 volts off the purple wire (if you have one). The mother board uses this to detect when the on button has been pressed, but a moderate current draw in addition may be tolerable. The purple wire should supply approximately 5v at 200 mA whenever the PSU is plugged into the wall.

I suggest you research the feasibility of tapping into this supply wire, normally called the "+5 volt standby" wire.

Andy

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Re-design (author)2009-08-28

Some powersupplies will have power to usb even on shutdown. I like to charge my mp3 while the computer is off.

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kevinhannan (author)2009-08-28

I think you've kind of answered you own question; It wouldn't be shut down if there was power out, now, would there? That would apply to molex and all the other power rails. Do what Kiteman says: if you need power after shut down, what is it you're trying to do?

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Kiteman (author)2009-08-28

If this question relates to a specific Instructable, you ought to post in in the comments of that instructable, or send a PM to the author.

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