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Keyboard issue

Posted: Tue Jan 23, 2018 3:12 pm UTC
by Yerushalmi
Hi all,

Today I turned on my laptop to discover that my right Ctrl key thinks it's a Tab key.

Pressing right-Ctrl acts like Tab in every way, in every program. No other key is acting incorrectly. I tried uninstalling/reinstalling keyboard drivers, rebooting, all the standard stuff.

And then I decided to check out what happens inside BIOS. And lo and behold: right-Ctrl key acts like Tab there as well.

That's generally a sign that this is a hardware problem, and that I have no recourse but to expensively purchase a replacement laptop keyboard.

But I'm posting here in the hope that all is not yet lost. Is there some software issue that can cause the same results? Is there anything I can do to salvage this? Help!

Re: Keyboard issue

Posted: Tue Jan 23, 2018 3:20 pm UTC
by Mutex
When was the last time the right-ctrl key was working properly? Seems odd, it could be a wiring fault that's suddenly occurred (did you drop any drinks or anything into the keyboard?). Other than that... if it's a config thing it would probably have to be a physical switch you flipped somewhere, it seems really unlikely the keyboard on a laptop would have such a switch.

Re: Keyboard issue

Posted: Tue Jan 23, 2018 4:22 pm UTC
by Yerushalmi
I don't remember anytime specific that I used the right control key as opposed to the left, but I use keyboard shortcuts prolifically (and often while walking around with the laptop, so one hand is gripping the laptop and the other is pressing the shortcut) so I can't imagine it will have been more than a day or two, possibly even less.

I haven't dropped any drinks on it, and I would imagine such a thing would affect more than just the one key. But I do have four kids and god only knows what they get up to when I'm not around.

I can't imagine such a config item either. If it is a wiring fault, what are the chances it'll fix itself or I can find a way to fix it?

Re: Keyboard issue

Posted: Tue Jan 23, 2018 5:24 pm UTC
by Tub
Does tab still work as tab, or has that suddenly become ctrl? If the keys are switched, I'd just switch them back via software (~/.Xmodmap on linux). You know, take the lazy solution.

Did you do a cold reboot (remove power and battery for a minute), then enter the bios directly? Still swapped? Then it's either an obscure bios feature, or a hardware problem.

You could also plug in an USB keyboard, see if those get swapped too. If they do, it's a bios or software issue.

If the notebook is serviceable, I'd open it, remove the keyboard, discard sand and breadcrumbs and clean the contacts.

Re: Keyboard issue

Posted: Tue Jan 23, 2018 7:51 pm UTC
by Yerushalmi
Nope. They're not swapped. Right-ctrl just acts like I have a second tab key.

I pulled off the Ctrl key and cleaned out under it but no luck.

Re: Keyboard issue

Posted: Mon Jan 29, 2018 8:14 am UTC
by Yerushalmi
So a couple of days later it just started working properly again.

It even took me a while to notice, because force of habit and muscle memory prevent one from realizing that keyboard shortcuts weren't no longer working.

So I'm guessing there was some droplet of water or something that was stuck in the system and causing a short, changing one bit of the signal sent by Ctrl, and it eventually evaporated.

Thanks for the help :)