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IT query, weird laptop screen behaviour?

pjgtech

pjgtech

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I know there's a few IT savvy peeps on here, so just asking to see if anyone has any ideas how to fix this?
I'm usually pretty good at IT myself, but this one has got me stumped!
My laptops (Asus TUF Gaming F15) screen has started playing up. NB: I'm using Win11.
When I first switch on the laptop, (this is my main laptop which I use everyday), I normally type in a bios password, which then goes to the windoze log in screen and a 2nd password.

However, its now not showing the screen at the first bios pw, the screen is blank, but there's a few very thin flashing lines at the top of the screen. So you can't see the screen or the pw prompt. However, as I know the pw prompt is there for the password, I type it in anyway and this takes me to the windoze pw screen, and the screen re-appears here so I can see the windoze pw prompt.....all good so far.
I log into windoze and its all good, the screen is fine, etc. But after about 30 seconds or so, the screen again goes blank again, apart from a few very thin lines at the top of the page, so I can't see anything again. Its very annoying!

But, the weird thing is if I unplug the mains lead from the laptop so its on battery, the screen is fine and comes back again. If I then plug the AC adaptor back into the laptop, the screen goes weird again!

I have taken the back cover off the laptop and had a look to see if there's any loose connections or anything obvious, but I can't see anything wrong.
If I fiddle with the mains lead, laptop lead plug, laptop socket, etc, nowt happens, so it looks like it's not a loose connection.
I have also checked that I have the latest GFX drivers, which I do.

Annoyingly as this is an older laptop, it only holds charge for about 2 hours, so I can use it on battery fine, but then when its re-charging I can't use it, as the screen goes blank when I plug in the adaptor.

I would love to know if anyone has any ideas what might be causing this and/or a fix?

Cheers
 
That’s a strange one, but the big clue is it only happens when the charger’s plugged in.

If it was the screen, cable or GPU properly failing, you’d expect it all the time, not working perfectly on battery. The fact it also does it before Windows loads rules out drivers as well.

First thing I’d try is a different charger. Failing PSUs can output unstable/noisy power and cause exactly this sort of behaviour.

Also worth noting those TUF laptops often switch to the dedicated GPU when on mains. If that’s playing up, it could explain it. You could try forcing it onto integrated graphics and see if it behaves…

If you plug into an external monitor on AC and that’s fine, it points more to the screen side. If that glitches too, it’s more likely GPU or motherboard power.

I’d definitely start with the charger though, easiest and most likely 🙏🏻 🍀
 
Possibly a failing PSU that's supplying the wrong voltage to the laptop. Personally I'd stop using it until a new PSU is acquired, to avoid damage.

Had a similar experience with my own Lenovo laptop, which would simply crash during boot when the PSU was connected but boot up fine from the battery. A new PSU solved the problem.
 
I would also look at the mains adapter first due to the behaviour when plugged in, as said if unstable it could well be the cause.
 
To echo the external screen comment, that should narrow it down to information sent by the hardware, or a failure in that getting to the LCD.
I'd have the screen ribbon cable off, wipe some paper across the contacts (both ends), and re fit.
 
MrDellski said:
those TUF laptops often switch to the dedicated GPU when on mains.
Click to expand...

Excellent logic there, if the graphics has suffered heat failure, as so many laptop GPU's do, and it went over to the failed route with mains power, it would provide these symptoms.
The Nvidia chips I've seen that have required reballing (which normally only buys a few more months) show part screen, or torn graphics.

Hat tip to that one.
 
Ok, so little update. I actually have two of these latops, one's mine and the other is the Wifes (mine is the faulty one and is slightly older than the wifes).
So I swapped the mains adaptor and lead with my wifes, and got exactly the same issue.
So it looks like its not the mains adaptor or the lead.
I have also tried plugging into different sockest around the house, and get the same issues, so looks like its not an issue with the socket I usually use in the house.
I have a pc monitor in my study, so will try connecting the laptop to that and see what happens.
I do have dual GFX card in this laptop, the Intel one and the GeForce RTX one, so will try maybe switching those anfd see what happens.
Cheers for the help.....
 
Ok, nuther little update, I went into nVidia settings and switched the GFX to built-in Intel, but did not change anything.
I went back in and changed the gfx to nVidia and that also made no difference, so looks like it happening whether it via the Intel built in GFX chip or the nVidia GFX chip?

Next I went upstairs and plugged the laptop into my PC monitor, (the connection is via HDMI), and on mains or on battery, both the laptop screen and monitor screen worked fine, both at same time.
But, if I unplugged the HDMI then obviously the monitor was no longer connected and the laptop screen went back to the very thin lines at the top, plug the HDMI back in and both the monitor and the laptop screen appear as normal!

I then took the back of the laptop off (again) and actually unscrewed and disconnected the bit/small block where the power lead connects to the laptop, and then reconnected it all, to make sure there were no loose connections, etc. Made no difference.
Lastly with the case off and being very careful not to touch anything! I tried wiggling it around a bit (with the laptop switched on) to see if the screen altered, flickered, etc, but nope, made no difference.

Stumped?
 
That extra testing actually narrows it down quite a bit.

You’ve ruled the charger out now, and also the GPU side of things. The key bit for me is that when you plug HDMI in, both the external screen and the laptop screen work fine. If it was GPU or motherboard related, you’d expect the issue to show on the external display as well.

That makes it look much more like the laptop panel itself (or the control electronics on it) is the issue. The fact it behaves differently depending on how it’s being driven ties in with that.

Based on what you’re seeing, it does look now more like the screen is the likely culprit rather than anything else.

:)
 
No going back now, Lol, screen is off!
Asus TUF F15 PG laptop screen repiar apr26 (2).webp
 
Screens are quite cheap, so I'm willing to risk it.
The YT vid I watched made it look easy to swap (hmmm, we'll see?)
Took me about 15 minutes to get the old screen off, so hopefully putting new one back in should not take lot longer, but again, well see.... :)
 
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