Keyboard switches off randomly for few seconds.

Dear Goodjers,
I've been searching for a topic with this sort of problem everywhere, but cannot find anything.

I left my pc for two weeks with my parents, and when I come back turns out 'keyboard does not work'. When plugged in it flashed 3 little lights (num lock, caps, etc) for a second but was completely dead and unresponsive. So I bought a new one.

I plug it in, it works, but then after few minutes it switches off (I can see num lock light goes dark) and turns on again after about 10 seconds (I can hear the sound of something being plugged in in windows). When it happens while playing a game, I get a rather big lag/2sec freeze. I tried using different usb port, I tried using converter and plugging it to ps2 port (purple one). I tried reinstalling windows.

Now it became more and more persistent, to the point I can barely write this post as it switches off every 30 sec or so.
Very annoying. Please point me in some direction with this.

USB I assume. Which port is it plugged into? Try one that's directly on the motherboard if it isn't already.

My next guess would be to look at your background tasks, although I'm not sure which one could disable/enable a USB device.

I assume your mouse is also plugged in using USB, and isn't experiencing any issues? Did the keyboard come with a purple USB/PS2 adapter that you could try?

Guys... really?

Slupczynski wrote:

I tried using different usb port, I tried using converter and plugging it to ps2 port (purple one). I tried reinstalling windows.

He tried that. I'm just not clear on whether the issue affects both tried keyboards on all ports.

So you get the same behavior both on the PS2 port and on all USB ports with two different keyboards? Is that accurate?

Well, good. I got today's moment of embarrassing oversight out of the way without creating another bug to worry about.

Well, to be fair, the question about the mouse is worth an answer too. I'd be very interested in hearing what's causing this if mouse functionality stays solid throughout all this.

I skimmed. In my experience with PS2 years ago it needed to be in at boot because it wouldn't autodetect it afterwards, hence the USB assumption.

Scratched wrote:

I skimmed. In my experience with PS2 years ago it needed to be in at boot because it wouldn't autodetect it afterwards, hence the USB assumption.

This actually isn't the case anymore. At least it isn't on my rig, I don't know if it's a universal thing or maybe motherboard/OS/driver specific or something. But I can plug my mechanical boards into the PS2 port and they just work. The only thing I have to change is the key repeat rate in the keyboard options. It always resets itself back to a very slow rate.

I've had similar issues in a USB3 port, but when I plugged into a USB2 port the problem went away. That doesn't explain why it would disappear when plugged into a PS2 port though. Do you have another keyboard you can try?

People, you don't read: P

He have two keyboards, he checked the PS/2 and USB, problem is the same.
Describe the exact steps against the vulnerability and behavior your PC.

I think... to solve this problem, you need a very competent person : (

Personally, I'd try the following:

Reset all settings in the system BIOS to factory defaults.
Perform a physical reset of the BIOS (usually shorting two pins or taking the battery off of the board for a few minutes).
Get the latest BIOS version for your system and flash it.

If none of those work, that would pretty much eliminate the system BIOS as a factor.

The next thing I'd concern myself with is the system power supply. If a portion of your power supply is overheating/failing that could be interrupting the 5v supply which USB and the PS2 ports require. Is the PSU dusty? Try cleaning it out.

EDIT: Upon thinking further, you could have a component that's failing and/or drawing too much power from the 5v rail as well. 5v tends not to be used as much in newer PCs. Newer hard drives and optical drives still use it for their circuits. PCI cards also can still use it. The older your computer is, the more likely you have components other than USB/PS2 which use the primary 5v. (Note: Your BIOS uses a different 5v rail altogether to do its thing, so main computer functions would not be impacted.)

Try disconnecting non-essential components like the optical drives or any PCI add-on cards. Do things work better? Is there one component which reintroduces the problem?

If all else fails to resolve the problem, I'd probably put first blame on the power supply and replace it.

I did remove the motherboard battery for few hours and it did reset. It was ok for few hours, but then came back to normal malfunctioning and with even more intensity. oO

I asked a friend to bring his keyboard over. It works fine for many hours now, been playing games, etc.
So it's 'good'. I have no clue if the problem will return at some point.

A friend took my keyboard in return and it works fine on his pc. No clue.

Could the fact that this is Logitech keyboard be a factor in this? (the one that's working currently).
All mine were some £6 cheapest not-branded products.

Weird. Never seen a keyboard fail in that way before. Since it works on the friend's machine, I would still say that your power supply isn't out of contention yet. To eliminate the power supply you could stress test the 5V rail. Try loading up USB with devices that draw power from it. Things like external drives and phones/tablets should give it a workout if you have access to some. If that doesn't cause any symptoms to manifest after some time, perhaps the keyboard does have a short or other issue which causes problems on your machine.

Adding more since I always seem to think of more after posting - your friend's keyboard may also tolerate lower voltages better than yours. If there are voltage drops on 5V, perhaps yours is the canary in the coal mine so to speak. I'll see what I can recommend for monitoring system voltages once I'm in front of a bigger screen later this morning, or maybe another Goodjer knows off hand.

EDIT: Good old SpeedFan still does system voltages and works on my machines here. You should expect to see between 4.75V and 5.25V in a system that is running properly.