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Power line noise wakes a sleeping desktop

V

voodoodrul

Senior member
I have been fighting to get to the bottom of this for over a year. Every time there is some sort of power line noise event (static or noise), my desktop wakes up.

Event viewer shows:
Wake Source: Device -USB Root Hub

I only have a keyboard and mouse connected to the USB ports.

My desktop is behind an APC XS 1500 UPS. It is the only thing connected to the UPS.

I have another power strip connected to another outlet in the same room. For example, I just merely plugged in the *power adapter* from a laptop I have - there was a little arc and noise on the power line caused by doing this. The moment this happens, the desktop wakes up. It is easily reproducible. All I have to do is unplug that laptop power adapter, wait 10 seconds, and plug it back into the power strip. Yes, this really happens.

Does anyone know how to prevent this from happening? I have already tried setting the device manager->power management options to not allow any of the relevant devices to wake the computer.. No luck.

I think I have narrowed it down to the keyboard as the culprit device, of all things. When the keyboard is not connected, this doesn't seem to happen. It's an old Saitek Eclipse.
 
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Check your settings on your wake up options in the BIOS. Usually you can turn wake-up options off and on. You can make it so only the spacebar on your keyboard can wake up the motherboard.

How do you know it is not the wiring in your house? Every time I go to use my HTPC I have to move my finger around on my wireless keyboard to wake it up. So what do you have hooked up on your USB ports? Only thing I have on my USB is my wireless adapter. I wonder if something like a USB webcam or microphone or mouse can wake it up? Vibration form passing trucks could be enough to wake it up. I have also seen cases where I get activity from interference from police radios. Are you getting wireless interference?

USB Root may be affected by something else.
 
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I've always had to shut mouse and keyboard wake off otherwise it randomly turns on. I always assumed it was some wireless interference that causes it to wake up. Or the cat is using my computer.
 
The only devices I have connected to any USB ports, for troubleshooting this problem, are the Saitek Eclipse keyboard and a Logitech G5 mouse.

I presume it's not the wiring in the house because the desktop is behind a UPS and should be well protected from wiring issues. I do know it's an RF or other noise related issue because it occurs exactly when a mild arcing occurs when I plug in the power adapter for the laptop.

It seems the keyboard is picking up the noise and waking up the system. I don't have BIOS options to limit it to a specific key, nor do I even have a way to disable waking from USB in this BIOS.. Very odd..

To make it even more confusing, if I leave the keyboard connected, and uncheck "Allow this device to wake the computer" in device manager, I can put it to sleep and test. Pressing any key on the keyboard does not wake the machine. But I can still wake it up *only* if this keyboard is connected to a port, even with waking disabled, and simply walk across the room and jam the laptop power adapter into a different outlet a few times.

I feel like a wizard some times.
 
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I was just looking at a website and power noise often comes from switching power supplies and sources like Dimmers. Maybe the culprit is your computer power supply? I wonder if there is a filter that will help for external noise. Maybe an electrical engineer is out there.
 
This could be a fun science experiment:

Keep repeating the wake up, but unplug your USB devices one at a time until it stops. Once you find the device that wakes it up. Verify it.

Now cover up that USB device with aluminum foil and try the same thing. At least that reduces it to power spikes through the wires.

If it continues then run a long extension cord far to the opposite side of the house and take that power strip and laptop adapter and do the same thing. Now do the same thing again without the extension but the power strip and laptop adapter are in a different circuit.

Have fun! 🙂
 
This same issue has been plaguing my desktop PC since I built it. 75% of the time when I get up in the morning, it has woken up from sleep all by itself. I have a dimmer on the incandescent fixture in the room, but the light is always OFF when the PC wakes up. It is probably one of my USB devices, since I have about 6 plugged in. Just been too lazy to dig for the fix. 😛
 
voodoodrul said:
I presume it's not the wiring in the house because the desktop is behind a UPS and should be well protected from wiring issues
Click to expand...

This is not true. Your Back-UPS XS 1500 is an inexpensive line-interactive model, not a true double-conversion UPS. This means that 99.9999% of the time, the PC's power connection is hooked straight up to the mains.

The UPS is acting like nothing more than a glorified power strip unless the power actually goes out for a few tens of microseconds. Since it sounds like you have bad wiring in your house, the MOVs in the surge suppression part of your UPS were likely shot long ago.
 
Thanks everyone! It's the keyboard for sure.. picking up RF; not even noise on the power circuit. I can reproduce the problem when the desktop isn't even plugged into the wall.

It's possible that my desktop has become self-aware, but it doesn't want me to talk about that..
 
Alas, it has returned. I spoke too soon. It seems if any USB device is connected at all, the problem can occur. It's almost as if the more devices that are connected, the more susceptible it is to picking up this RF noise and waking the system.

Why the crap is sleep/resume still such hassle for desktops in 2014?

Grumble.
 
I think I'd be more concerned about what is generating such powerful RF noise when plugging and unplugging power cables. You should not be getting noticeable arcs from residential wiring. I'm not an electrician, but I suspect you have a bad or non-existent ground.
 
mfenn said:
I think I'd be more concerned about what is generating such powerful RF noise when plugging and unplugging power cables. You should not be getting noticeable arcs from residential wiring. I'm not an electrician, but I suspect you have a bad or non-existent ground.
Click to expand...

Thanks mfenn, but the problem occurs with minor static discharge as well, and there is nothing wrong with the wiring here. Try this: take any laptop power adapter into a dark room. Look at the socket as you plug it in. I guarantee you will get a visible spark maybe 1 in 4 tries. That's enough to wake this machine roughly 50% of the time.

This morning I set my laptop on my desk. I plugged the laptop into the power adapter. Boom, desktop woke up.
 
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Last week I noticed that if I have static I can touch the case anywhere and it will power on. Corsair 650D. I haven't looked into this further but I will.
 
Try unplugging the USB headers from your motherboard. It could be that there is a poor ground connection in your case's headers and that is picking up enough RF noise make the PC think that a USB device is trying to send data.
 
mfenn said:
Try unplugging the USB headers from your motherboard. It could be that there is a poor ground connection in your case's headers and that is picking up enough RF noise make the PC think that a USB device is trying to send data.
Click to expand...

Good suggestion mfenn. I'll give that a shot. For now I'm trying to see if it ever occurs when this particular keyboard and mouse are not connected. If it doesn't, then I think it's either the ports they connect to, or the devices themselves.

It's time to replace these anyway, so I might just do that.
 
I replaced the keyboard (Saitek Eclipse) and mouse (Logitech G5) with a Logitech K70 keyboard and Logitech G500s mouse. The issue appears to be resolved.

Freakin' bizarre.
 
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