Question Lenovo 320-15AST works fine, but has no backlight on the built-in screen ?

[DirtyMinge]

Title, really. It's the same device from my other post, but another problem appeared. There's picture, but there's no backlight. I installed windows 10 and official Lenovo drivers, but nothing. It works fine on an external screen and I could finally pat myself on the back because I got its specs and model right.

I've fiddled with the display cable more than I should, to no avail. I'm pretty sure it seats in the connector just fine.

It's definitely between the cable and the panel. Short of swapping the panel and (possibly) cable, is there any way to troubleshoot, so I can find out where exactly the problem is located? But some random Googling got me thinking: does Lenovo employ some kind of BIOS-level LCD panel blacklist?

 

[Lutfij]

If you're getting display out to an external panel, then the issue is with the panel of the laptop. Have you tried powering the laptop without an external monitor? It's not a blacklist per se, it's about getting the right panel on the laptop, meaning panels that are meant for the laptop. Putting a panel that's meant for another laptop(brand or model) in spite of having the right connector pins can be hit or miss.

 

[DirtyMinge]

Have you tried powering the laptop without an external monitor?

It shows a picture, but I have to shine a flashlight on the monitor to see it, because the backlight doesn't turn on.

It's not a blacklist per se, it's about getting the right panel on the laptop, meaning panels that are meant for the laptop. Putting a panel that's meant for another laptop(brand or model) in spite of having the right connector pins can be hit or miss.

I mention a possible software blacklist because I'm aware of some Thinkpads which detect that a 3rd party LCD panel is installed and lock the brightness to the max. I figured the inverse would be possible.

So no other way of going about it than to change out the panel itself then?

 

[Lutfij]

Could be similar to Mac's where a part of the board responsible for the display(LVDS connector for your laptop or perhaps another part of the power delivery for the display) might be compromised hence the no backlight situation. If you're handy with a multimeter, perhaps you can identify the culprit.