Thinkpad L540 - Screen problem, strange not persistent line

[Insomniac1971]

Can any of you experts pin point why this is happening on the screen?

I bought this second hand laptop on august 30 2024, from original owner, no history of repair. And everything worked fine, except for defective keyboard and some screen bleed in right side edge.

Then I replaced the keyboard and this started about a week later, at first it were 1 blinking not persistent white line, now a month later its 2 lines.

It happens in Bios, Windows and Linux Mint 20.2 cinnamon. So it must be hardware.


ThinkPad L540 20AUA0F4JP serial R902K1R2
Core i5 4200m with Intel HD graphics 4600
16Gb ram
249Gb SSD
New UK keyboard
AU Optronics B156xtn02.6 LCD EDP panel HD 1366x768 (original build)
New Cmos battery

I do the upgrades myself.

I have unplugged the LCD cable from the motherboard and cleaned contact points. Replaced the thermal paste on the CPU. Cleaned fan.

I prefer not to take the LCD panel bezel apart, unless I have to replace the screen, as it can break easily. So if this is caused by something else than Failing LCD or bad LCD cable, I would gladly check that first

I have seen a lot in my 36 years in IT as Technician and Consultant, but I have not seen this before.

I have seen failing screens before, but the line were persistent, not like this - then again this is the first time I have an EDP LCD, so I don't know if that is a common problem.

And if it were the LCD cable, why a second white line?

Could this be caused by the keyboard, are there any history of OEM replacement Keyboards causing this odd behaviour?

I can live with it for now until I have enough money to buy replacement LCD, if that is what is needed.

Thank you in advance

Jan

Video here:

https://drive.google.com/file/d/1tkSfgD ... p=drivesdk