Question Built in keyboard stops working when charger is plugged in

[thuverx]

Hey there, I've seen multiple posts regarding this issue. But none seem to fit exactly to mine. So I've decided to create a new thread.

I have the Lenovo Legion y540-15irh 81sx, about 3 years old, so no more warranty. I've been trying to figure out why my keyboard has stopped working while the charger is plugged in.
Here's some testing I did:

• By plugged in I mean, started with the charger plugged in. Removing it while the system is active does not fix the issue
• This is also not fixed by restarting. And needs a full power down to function again (without the charger plugged in).
• The keyboard works pre bios, I can press F2 and get into the bios fine.
• In the bios the keyboard doesn't work. This includes the boot menu.
• In windows the keyboard doesn't work.
• The keyboard backlight keys (FN + Space) works, and cycles the backlight intensity.
• The in software (Lenovo vantage) backlight button works. And switches the backlight on and off.
• The brightness function keys do work. Both up and down.
• External keyboard works, trackpad too.

Things I've tried:

• Windows reinstall (Windows 10), multiple times.
• Update drivers.
• Update bios.
• Removed keyboard drivers and restarted.
• Nearly every setting in the bios.

I sadly can't use Lenovo Vantage auto update as some stupid mistake of mine trying to fix this caused bios chip to stop functioning. And so it has been replaced (By a third party), and now doesn't have a serial number on the bios anymore.
Though I have used Lenovo's own support page for my laptop and downloaded drivers from there.

One thing that might be of note (I don't know, I'm not an expert). Is that I have removed the original m.2 drive and am using a 500gb SSD instead.

I am really at a loss here, I really just want to use my laptop again. I really hope someone here knows a fix. Thanks in advance!

 

[Lutfij]

Either there's a part of the motherboard causing a short with the keyboard(either the ribbon cable or there's a key being depressed continuously). Have you tried using Keyboardtester to see if any key is pressed from the get go(OS GUI login)?

And so it has been replaced (By a third party), and now doesn't have a serial number on the bios anymore.
That might very well be the short...considering that the laptop might not have been flashed with the right BIOS version. I'm curious though, how are you stating that the BIOS is up to date?

 

[thuverx]

Have you tried using Keyboardtester to see if any key is pressed from the get go(OS GUI login)

No I have not, I don't really know how. Could you be so kind to point me to some resources (Or what to google)?

I'm curious though, how are you stating that the BIOS is up to date?

When it was replaced it had a bios version with a similar name, just an older version.
It now has the bios on it that I downloaded from Lenovo themselves. (BHCN44WW ) laptops and netbooks :: legion series :: legion y540 15irhcontentdetail - Lenovo Support US

And I would like to add that this keyboard issue was the reason I tried to "fix the bios" by myself (As I thought that might help). So the issue was already there before the bios was replaced.

I hope this explains things a bit!

 

[Aggu]

Did you manage to figure out a solution? I'm having the same issue or a similar one at least, keyboard works fine when the charger isnt in while booting.
From that point on it seems to work but kind of a hassle to have to go around that every time.

It also tries to install a software update for the keyboard if it doesnt work and that is just annoying having it randomly pop up.